Income Taxes - Unrecognized Tax Benefis (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]
Total uncertain tax position liabilities as of January 1,	$ 7,278	$ 5,557	$ 1,846
Current year acquisitions	911	0	0
Increases related to current year tax positions	0	347	5,169
Changes in tax positions of a prior period	0	1,934	11
Lapse of statute of limitations	(342)	0	(1,469)
Settlements with taxing authorities	(187)	(560)	0
Total uncertain tax position liabilities as of December 31,	$ 7,660	$ 7,278	$ 5,557