Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0000039899 (http://www.sec.gov/CIK)

Debt Disclosure [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Debt Disclosure [Abstract]
Long-term debt	Our long-term debt is summarized below (in thousands): Dec. 31, 2016 Dec. 31, 2015 Unsecured floating rate term loan due quarterly through August 2018 $ 52,100 $ 83,700 VIE unsecured floating rate term loans due quarterly through December 2018 1,292 1,938 Unsecured floating rate term loan due quarterly through June 2020 140,000 180,000 Unsecured floating rate term loan due quarterly through September 2020 285,000 — Borrowings under revolving credit agreement expiring June 2020 635,000 720,000 Unsecured notes bearing fixed rate interest at 10% due April 2016 — 193,429 Unsecured notes bearing fixed rate interest at 7.125% due September 2018 — 70,000 Unsecured notes bearing fixed rate interest at 5.125% due October 2019 600,000 600,000 Unsecured notes bearing fixed rate interest at 5.125% due July 2020 600,000 600,000 Unsecured notes bearing fixed rate interest at 4.875% due September 2021 350,000 350,000 Unsecured notes bearing fixed rate interest at 6.375% due October 2023 650,000 650,000 Unsecured notes bearing fixed rate interest at 5.50% due September 2024 325,000 325,000 Unsecured notes bearing fixed rate interest at 7.75% due June 2027 200,000 200,000 Unsecured notes bearing fixed rate interest at 7.25% due September 2027 240,000 240,000 Total principal long-term debt 4,078,392 4,214,067 Debt issuance costs (27,615 ) (31,800 ) Other (fair market value adjustments and discounts) (7,382 ) (12,605 ) Total long-term debt 4,043,395 4,169,662 Less current portion of long-term debt maturities of VIE loans 646 646 Long-term debt, net of current portion $ 4,042,749 $ 4,169,016
Schedule of Annual Maturities of Long-Term Debt	The following schedule of annual maturities of the principal amount of total debt assumes we use available capacity under our revolving credit agreement to refinance unsecured floating rate term loans and fixed rate notes due in 2017 through 2018. Based on this refinancing assumption, all of the obligations other than the VIE unsecured floating rate term loan due prior to 2019 are reflected as maturities for 2019 and beyond. In thousands of dollars 2017 (1) $ 646 2018 (1) 646 2019 700,000 2020 (2) 1,612,100 2021 350,000 Thereafter 1,415,000 Total $ 4,078,392 (1) Amortization of term debt due in 2017 and 2018 is assumed to be repaid with funds from the revolving credit agreement, which matures in 2020. Excluding our ability to repay funds with the revolving credit agreement, contractual debt maturities are $132 million and $121 million in 2017 and 2018, respectively. (2) Assumes current revolving credit agreement borrowings comes due in 2020 and credit facility is not extended.