Income Taxes (Schedule of Components of Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ 80,360	$ 162,639	$ 120,634
Current State Tax Expense (Benefit)	13,663	14,301	11,252
Current Foreign Tax Expense (Benefit)	25,001	17,382	22,946
Current Income Tax Expense (Benefit)	119,024	194,322	154,832
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	34,636	(38,416)	12,140
Deferred State Income Tax Expense (Benefit)	3,627	(2,436)	2,515
Deferred Foreign Income Tax Expense (Benefit)	(4,896)	(7,813)	(3,013)
Deferred Income Tax Expense (Benefit)	33,367	(48,665)	11,642
Tax expense (benefit) relating to uncertain tax positions, including accrued interest	3,915	5,084	(1,612)
Income Tax Expense (Benefit)	$ 156,306	$ 150,741	$ 164,862