Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Components Of Income Tax Expense Benefit Continuing Operations [Abstract]
Lease liabilities	$ 211,524	$ 181,607
Deferred compensation	79,068	80,389
Accrued expenses	73,835	26,166
Receivable reserves	41,963	33,199
Net operating loss carryforwards	32,727	28,781
Other	3,311	3,210
Total deferred tax assets	442,428	353,352
Valuation allowance	(11,740)	(5,042)
Deferred tax assets	430,688	348,310
Lease ROU asset	(210,670)	(180,598)
Goodwill and other intangibles	(51,189)	(46,625)
Depreciation	(15,371)	(7,231)
Unrealized gain on investments	(11,585)	(5,619)
Prepaid expenses	(5,396)	(3,857)
Total deferred tax liabilities	(294,211)	(243,930)
Net deferred tax asset	$ 136,477	$ 104,380