2013 | 2012 | |||||
Balance as of January 1 | $ | 53,835 | 46,087 | |||
Additions based on tax positions related to the current year | 3,840 | 3,142 | ||||
Additions for tax positions of prior years | 15,275 | 17,006 | ||||
Reductions for tax positions of prior years | (5,736 | ) | (3,571 | ) | ||
Reductions resulting from the lapse of the statute of limitations | (6,075 | ) | (1,764 | ) | ||
Settlements with taxing authorities | (4,594 | ) | (7,065 | ) | ||
Balance as of December 31 | $ | 56,545 | 53,835 | |||