Summary of Significant Accounting Policies (Other Expense, Net) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Write-off of deposits and pre-acquisition costs	$ (12,390,000)	$ (13,116,000)	$ (16,992,000)
Amortization of intangible assets	(19,685,000)	(14,200,000)	(13,800,000)
Loss on debt retirements	0	(4,927,000)	(76,000)
Interest income	6,837,000	16,739,000	7,593,000
Interest expense	(4,248,000)	(584,000)	(618,000)
Equity in earnings of unconsolidated entities	1,880,000	747,000	2,690,000
Miscellaneous, net	9,780,000	1,865,000	7,354,000
Total other expense, net	$ (17,826,000)	$ (13,476,000)	$ (13,849,000)