Income Taxes - Provision Benefit for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
U.S.	$ 91,641	$ 67,668	$ 73,059
State and local	9,342	4,503	6,188
Foreign	50,775	42,540	30,630
Total current	151,758	114,711	109,877
Deferred
U.S.	(36,390)	(6,249)	7,125
State and local	3,305	(331)	(1,017)
Foreign	(657)	(10,728)	(6,447)
Total deferred	(33,742)	(17,308)	(339)
Total provision for income taxes	$ 118,016	$ 97,403	$ 109,538