Income Taxes - Schedule of Income Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes
Domestic									$ 52,798	$ 77,346	$ 50,145
Foreign									13,366	11,516	11,870
Income before provision for income taxes	$ 18,436	$ 18,961	$ 17,738	$ 11,029	$ 45,859	$ 10,311	$ 20,274	$ 12,418	$ 66,164	$ 88,862	$ 62,015