Income Taxes (Schedule of Provision for Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ (6,000)	$ 85,800	$ (4,500)
Foreign	11,500	3,000	9,400
State and local	(800)	6,700	3,300
Total current income tax expense	4,700	95,500	8,200
Deferred:
Federal	18,200	6,100	25,700
Foreign	(7,500)	(6,800)	(19,900)
State and local	7,600	(3,000)	(2,000)
Total deferred income tax expense	18,277	(3,935)	3,925
Provision for income taxes	22,942	91,784	11,957
Continuing Operations [Member]
Deferred:
Total deferred income tax expense	$ 18,300	$ (3,700)	$ 3,800