Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of unrecognized tax benefits:
Gross tax contingencies - beginning of the period	$ 55,951	$ 51,146	$ 37,563
Gross additions based on tax positions related to the current year	3,484	3,984	5,985
Gross additions for tax positions of prior years	979	13,717	20,275
Gross reductions for tax positions of prior years	(3,588)	(2,699)	(1,370)
Lapses of statutes	(9,141)	(5,350)	(1,312)
Settlements	0	(4,847)	(9,995)
Gross tax contingencies - end of the period	$ 47,685	$ 55,951	$ 51,146