Income Taxes - Uncertain Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in unrecognized tax benefits
Balance at beginning of year	$ 9,152	$ 4,276	$ 6,228
Additions for tax positions related to current year	1,038	5,596	244
Additions for tax positions relating to prior years	233	143	199
Reductions for tax positions relating to prior years	(2,826)		(2,345)
Reductions due to the lapse of the applicable statute of limitations	(39)	(642)	(38)
Settlements	(106)	(221)	(12)
Balance at end of year	7,452	9,152	$ 4,276
Unrecognized tax benefits that would impact effective tax rate if recognized	5,400
Accrued interest and penalties related to unrecognized tax benefits	$ 300	$ 200