Income Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S. Federal:
Current									$ (10,582)	$ (18,789)	$ (56,743)
Deferred									6,205	11,577	61,514
U.S. Federal: Total									(4,377)	(7,212)	4,771
U.S. State and Local:
Current									(2,569)	(9,142)	(12,214)
Deferred									4,016	8,043	866
U.S. State and Local: Total									1,447	(1,099)	(11,348)
International:
Current									4,993	9,993	11,308
Deferred									4,664	(14,689)	1,685
International: Total									9,657	(4,696)	12,993
Total current									(8,158)	(17,938)	(57,649)
Total deferred									14,885	4,931	64,065
Provision (benefit) for income taxes	$ (813)	$ 554	$ 17,016	$ (10,030)	$ 344	$ (24,895)	$ 3,724	$ 7,820	$ 6,727	$ (13,007)	$ 6,416
Effective tax rate									(3.60%)	(47.90%)	3.40%