Income Taxes (Schedule of Components of Income Tax Expense (Benefit) ) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Current income tax expense	$ 88,914	$ 149,106	$ 304,726
Deferred income tax expense	45,736	48,331	59,243
Total income tax expense	$ 134,650	$ 197,437	$ 363,969