Income Taxes (Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current income taxes:
Current income taxes: U.S. federal	$ 22,700	$ 327,697	$ 247,917
Current income taxes: State and local	14,521	17,811	31,939
Current income taxes: Foreign	58,669	73,248	61,712
Total current income taxes	95,890	418,756	341,568
Deferred income taxes:
Deferred income taxes: U.S. federal	54,983	(17,419)	(16,167)
Deferred income taxes: State and local	19,076	(3,046)	(22,115)
Deferred income taxes: Foreign	14,397	(55,126)	4,273
Total deferred income taxes	88,456	(75,591)	(34,009)
Income tax expense (benefit)	$ 184,346	$ 343,165	$ 307,559