Income Taxes - Summary of Activity Related to Uncertain Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of activity related to uncertain tax positions:
Balance at January 1,	$ 3,561	$ 2,644	$ 1,960
Additions Based on Tax Positions Related to the Current Year	258	331	311
Additions for Tax Positions of Prior Years	293	1,176	928
Prior Year Reductions	(776)	(1)	(370)
Statute Expirations	(609)	(589)	(94)
Settlements	(133)	0	(91)
Balance at December 31,	$ 2,594	$ 3,561	$ 2,644