Income Taxes (Schedule Of Temporary Differences That Give Rise To Deferred Tax Assets (Liabilities)) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Taxes [Abstract]
Accrued liabilities	$ 42,840	$ 42,151
Lease liabilities	35,936	35,888
Implicit price concessions	7,744	7,031
Stock compensation expense	6,976	4,047
State net operating loss carryforwards	1,920	2,030
Other	920	888
Deferred income tax assets	96,336	92,035
Amortization of intangible assets	(41,925)	(40,619)
Accelerated tax depreciation	(32,489)	(32,788)
Right of use lease assets	(35,416)	(31,686)
Current assets	(3,858)	(3,921)
Market valuation of investments	(3,189)	(2,382)
State income taxes	(2,504)	(1,161)
Other	(138)	(142)
Deferred income tax liabilities	(119,519)	(112,699)
Net deferred income tax liabilities	$ (23,183)	$ (20,664)