Income Taxes - Reconciliation of Total Amounts of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 814	$ 4,573	$ 6,110
Gross increases—tax positions in prior years	92	0	1
Gross decreases—tax positions in prior years	0	(1,807)	(333)
Gross increases—tax positions in current year	114	120	35
Settlements	0	(520)	0
Lapse of statute of limitations	(289)	(1,552)	(1,240)
Balance at end of period	$ 731	$ 814	$ 4,573