Income Taxes (Provision For Income Taxes/(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
Components Of Income Tax Expense Benefit Continuing Operations [Abstract]
Current taxes: Federal									$ 123,802	$ 89,971	$ (29,396)
Current taxes: State									30,464	36,070	(334)
Current taxes: Foreign									1,684	99	(1,734)
Current taxes: Total									155,950	126,140	(31,464)
Deferred taxes: Federal									(7,027)	11,932	114,842
Deferred taxes: State									4,266	2,267	1,728
Deferred taxes: Foreign									(4,037)	55	1,559
Deferred Income Tax Expense (Benefit), Total									(6,798)	14,254	118,129
Provision for income taxes	$ 31,925	$ 40,632	$ 38,225	$ 38,370	$ 41,869	$ 36,672	$ 31,060	$ 30,793	$ 149,152	$ 140,394	$ 86,665