Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount	$ 20,700
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	1,000		$ 954	$ 0	$ 0
Foreign Earnings Repatriated		$ 19,800
Net operating loss carryforwards	0		0
Foreign net operating loss carryforwards	$ 1,250		$ 1,250