Income Taxes (Provision for Income Taxes Components) (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense (Benefit), Continuing Operations [Abstract]
U.S. Federal, Current									$ 46,059	$ 10,743	$ 56,342
State and Local, Current									2,240	5,930	6,325
Non-U.S., Current									10,924	10,079	8,463
Total income tax, Current									59,223	26,752	71,130
U.S. Federal, Deferred									16,718	(153,217)	33,959
State and Local, Deferred									(23,809)	3,306	(5,164)
Non-U.S., Deferred									(32)	3,459	(18,725)
Total income tax, Deferred									(7,123)	(146,452)	10,070
U.S. Federal, Total									62,777	(142,474)	90,301
State and Local, Total									(21,569)	9,236	1,161
Non-U.S., Total									10,892	13,538	(10,262)
Total provision for income tax	$ 12,400	$ 10,000	$ 16,100	$ 13,600	$ (159,700)	$ 13,400	$ 23,900	$ 2,700	$ 52,100	$ (119,700)	$ 81,200