Income Taxes (Schedule of Components of Income Tax Expense) (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
U.S. Federal									$ 15,905	$ 20,634	$ 65,856
U.S. State									4,717	3,240	2,732
Non-U.S.									1,336	1,436	2,030
Current income tax expense (benefit)									21,958	25,310	70,618
Deferred:
U.S. Federal									(9,386)	(7,509)	17,397
U.S. State									(8,033)	(8,973)	(787)
Deferred income tax expense (benefit)									(17,419)	(16,482)	16,610
Income Tax Expense / Effective Rate	$ 4,782	$ 2,415	$ (1,808)	$ (850)	$ 301	$ (690)	$ 3,032	$ 6,185	$ 4,539	$ 8,828	$ 87,228