Equity Investees (Schedule of Operations for Equity Investees) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
INCOME STATEMENT DATA:
Total revenues	$ 1,824,655	$ 2,480,820	$ 2,912,770
Operating income	(245,958)	272,703	170,248
Net Income	(416,678)	95,999	(6,075)
Equity Method Investment, Nonconsolidated Investee or Group of Investees
INCOME STATEMENT DATA:
Total revenues	214,687	209,674	180,056
Operating income	153,640	155,920	129,160
Net Income	$ 147,560	$ 139,436	$ 115,669