Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Insurance and claims accruals	$ 55,233	$ 54,913
Compensation - related accruals	12,203	16,054
Allowance for uncollectible accounts	3,958	4,070
Operating lease liabilities	7,033	2,530
Other	1,644	2,844
Gross deferred income tax assets	80,071	80,411
Property and equipment	305,002	308,145
Investments in equity securities	10,985	0
Prepaid expenses	7,269	6,333
Operating lease right-of-use assets	6,955	2,485
Investment in partnership	17,076	0
Other	1,283	1,318
Gross deferred income tax liabilities	348,570	318,281
Deferred income tax liabilities, net	$ 268,499	$ 237,870