Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ (1,668)	$ (702)	$ (3,237)
State and local	643	199	(762)
Foreign	1,125	1,385	1,224
Total current income tax provision	100	882	(2,775)
Deferred:
Federal	(61,655)	3,523	1,756
State and local	(2,107)	1,696	519
Foreign	528	810	258
Total deferred income tax provision	(63,234)	6,029	2,533
Federal	(63,323)	2,821	(1,481)
State and local	(1,464)	1,895	(243)
Foreign	1,653	2,195	1,482
Total income tax expense	$ (63,134)	$ 6,911	$ (242)