Segment Information | Our segment information is as follows (in thousands): | | | | | | | | | | | | | For the years ended December 31, | | | | | | | 2016 | | 2015 | | 2014 | Revenues | | | | | | Supply Chain Management Group | $ | 205,475 |
| | $ | 196,772 |
| | $ | 172,482 |
| Aviation Group | 133,466 |
| | 119,729 |
| | — |
| Federal Services Group | 306,109 |
| | 166,973 |
| | 190,761 |
| IT, Energy and Management Consulting Group | 46,740 |
| | 50,508 |
| | 60,828 |
| Total revenues | $ | 691,790 |
| | $ | 533,982 |
| | $ | 424,071 |
| | | | | | | Operating income: | |
| | |
| | |
| Supply Chain Management Group | $ | 34,632 |
| | $ | 35,453 |
| | $ | 29,694 |
| Aviation Group | 12,823 |
| | 10,635 |
| | — |
| Federal Services Group | 4,185 |
| | 2,071 |
| | 3,452 |
| IT, Energy and Management Consulting Group | 3,611 |
| | 4,731 |
| | 6,634 |
| Corporate | (3,722 | ) | | (2,351 | ) | | (2,850 | ) | Operating income | $ | 51,529 |
| | $ | 50,539 |
| | $ | 36,930 |
| | | | | | | Depreciation and amortization expense: | |
| | |
| | |
| Supply Chain Management Group | $ | 6,445 |
| | $ | 7,074 |
| | $ | 5,373 |
| Aviation Group | 5,461 |
| | 5,865 |
| | — |
| Federal Services Group | 12,752 |
| | 10,635 |
| | 11,320 |
| IT, Energy and Management Consulting Group | 1,388 |
| | 1,967 |
| | 2,077 |
| Total depreciation and amortization | $ | 26,046 |
| | $ | 25,541 |
| | $ | 18,770 |
| | | | | | | Capital expenditures: | |
| | |
| | |
| Supply Chain Management Group | $ | 4,195 |
| | $ | 7,544 |
| | $ | 2,524 |
| Aviation Group | 1,459 |
| | 959 |
| | — |
| Federal Services Group | 85 |
| | 78 |
| | 230 |
| IT, Energy and Management Consulting Group | 9 |
| | 16 |
| | 199 |
| Corporate | 1,624 |
| | 1,965 |
| | 461 |
| Total capital expenditures | $ | 7,372 |
| | $ | 10,562 |
| | $ | 3,414 |
|
| | | | | | | | | | December 31, | | 2016 | | 2015 | Total assets: | | | | Supply Chain Management Group | $ | 185,004 |
| | $ | 188,352 |
| Aviation Group | 291,500 |
| | 263,226 |
| Federal Services Group | 60,506 |
| | 38,772 |
| IT, Energy and Management Consulting Group | 47,043 |
| | 47,000 |
| Corporate | 77,786 |
| | 80,004 |
| Total assets | $ | 661,839 |
| | $ | 617,354 |
|
|
Revenue by Customer | Our revenue by customer is as follows for the years ended December 31, (in thousands): | | | | | | | | | | | | | | | | | | | | | | Revenues by Customer Years ended December 31, | Customer | | 2016 | | % | | 2015 | | % | | 2014 | | % | U. S. Postal Service | | $ | 181,215 |
| | 26.2 | | $ | 184,876 |
| | 34.6 | | $ | 167,268 |
| | 39.4 | | | | | | | | | | | | | | U.S. Navy | | 190,155 |
| | 27.5 | | 98,887 |
| | 18.5 | | 88,007 |
| | 20.7 | U.S. Army | | 139,764 |
| | 20.2 | | 80,086 |
| | 15.0 | | 101,714 |
| | 24.0 | U.S. Air Force | | 3,482 |
| | 0.5 | | 3,558 |
| | 0.7 | | 3,323 |
| | 0.8 | Total - DoD | | 333,401 |
| | 48.2 | | 182,531 |
| | 34.2 | | 193,044 |
| | 45.5 | | | | | | | | | | | | | | Commercial Aviation | | 131,067 |
| | 19.0 | | 119,729 |
| | 22.4 | | — |
| | — | Other Commercial | | 10,721 |
| | 1.5 | | 4,653 |
| | 0.9 | | 3,680 |
| | 0.9 | Total - Commercial | | 141,788 |
| | 20.5 | | 124,382 |
| | 23.3 | | 3,680 |
| | 0.9 | | | | | | | | | | | | | | Department of Energy | | 11,708 |
| | 1.7 | | 16,020 |
| | 3.0 | | 19,000 |
| | 4.5 | Social Security Administration | | 9,762 |
| | 1.4 | | 9,666 |
| | 1.8 | | 10,153 |
| | 2.4 | Other Government | | 13,916 |
| | 2.0 | | 16,507 |
| | 3.1 | | 30,926 |
| | 7.3 | Total - Other Civilian Agencies | | 35,386 |
| | 5.1 | | 42,193 |
| | 7.9 | | 60,079 |
| | 14.2 | | | | | | | | | | | | | | Total | | $ | 691,790 |
| | 100.0 | | $ | 533,982 |
| | 100.0 | | $ | 424,071 |
| | 100.0 |
|
Revenue from External Customers by Geographic Areas | Revenue by geography is based on the billing address of the customer. Our revenue by geographic area is as follows (in thousands): | | | | | | | | | | | | | | | | Years ended December 31, | | | 2016 | | 2015 | | 2014 | United States | | $ | 638,726 |
| | $ | 481,466 |
| | $ | 422,519 |
| Other Countries (1) | | 53,064 |
| | 52,516 |
| | 1,552 |
| Total revenue | | $ | 691,790 |
| | $ | 533,982 |
| | $ | 424,071 |
|
(1) No individual country, other than disclosed above, exceeded 10% of our total revenue for any period presented. |