Income Taxes - Schedule of Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
Federal									$ 3,568	$ 8,002	$ 5,451
Foreign									4,345	2,855	3,019
State and local									1,169	943	1,029
Total current expense									9,082	11,800	9,499
Deferred expense
Federal									45,934	3,222	2,333
Foreign									(9)	13	25
State and local									569	238	173
Total deferred expense									46,494	3,473	2,531
Provision for income tax expense	$ 44,693	$ 3,091	$ 4,762	$ 3,030	$ 3,097	$ 4,632	$ 4,285	$ 3,259	$ 55,576	$ 15,273	$ 12,030