Income Taxes - Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Gross unrecognized tax benefits at beginning of year	$ 7,024	$ 14,824	$ 16,386
Increases in tax positions for prior years	859	0	2,692
Decreases in tax positions for prior years	(96)	(525)	0
Decreases from lapse in statute of limitations	(2,776)	(7,275)	(2,670)
Settlements	0	0	(1,584)
Gross unrecognized tax benefits at end of year	$ 5,011	$ 7,024	$ 14,824