Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Components Of Income Tax Expense Benefit Continuing Operations [Abstract]
Lease liabilities	$ 181,607
Deferred compensation	80,389	$ 74,916
Receivable reserves	33,199	30,252
Net operating loss carryforwards	28,781	29,699
Accrued expenses	26,166	19,832
Unrealized loss on investments		10,635
Other	3,210	3,066
Total deferred tax assets	353,352	168,400
Valuation allowance	(5,042)	(3,944)
Deferred tax assets	348,310	164,456
Lease ROU asset	(180,598)
Goodwill and other intangibles	(46,625)	(42,045)
Depreciation	(7,231)	(6,629)
Unrealized gain on investments	(5,619)
Prepaid expenses	(3,857)	(3,774)
Total deferred tax liabilities	(243,930)	(52,448)
Net deferred tax asset	$ 104,380	$ 112,008