Income Taxes - Reconciliation of Total Amounts of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 4,573	$ 6,110	$ 7,097
Gross increases-tax positions in prior years	0	1	559
Gross decreases-tax positions in prior years	(1,807)	(333)	(369)
Gross increases-tax positions in current year	120	35	38
Settlements	(520)	0	0
Lapse of statute of limitations	(1,552)	(1,240)	(1,215)
Balance at end of period	$ 814	$ 4,573	$ 6,110