Consolidated Balance Sheets - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash	$ 11,070,000	$ 18,526,000
Accounts receivable, net	360,470,000	321,810,000
Operating supplies	18,369,000	17,976,000
Prepaid expenses	44,534,000	32,080,000
Other current assets	72,237,000	51,872,000
Total current assets	506,680,000	442,264,000
Property and equipment:
Land and land improvements	28,177,000	26,023,000
Buildings and leasehold improvements	99,964,000	80,768,000
Equipment	684,562,000	663,207,000
Less accumulated depreciation	500,025,000	501,459,000
Property, Plant and Equipment, Net	312,678,000	268,539,000
Right-of-use assets - operating leases	110,248,000	104,612,000
Marketable securities and other investments	34,565,000	28,909,000
Loss Contingency, Receivable	200,000,000	7,500,000
Other assets	11,875,000	15,341,000
Intangible assets, net	20,214,000	18,949,000
Goodwill	84,800,000	70,107,000
Total assets	1,281,060,000	956,221,000
Property and equipment	812,703,000	769,998,000
Current liabilities:
Current portion of long-term debt, finance lease liabilities and short-term debt	45,766,000	26,872,000
Current portion of operating lease liabilities	39,043,000	34,652,000
Accounts payable	59,140,000	50,171,000
Accrued expenses	81,944,000	77,454,000
Self-insurance accruals	50,379,000	56,221,000
Total current liabilities	276,272,000	245,370,000
Long-term debt	148,261,000	155,777,000
Senior unsecured notes	134,916,000	74,991,000
Lease liabilities - finance leases	13,544,000	9,481,000
Lease liabilities - operating leases	71,134,000	68,878,000
Self-insurance accruals	84,053,000	77,926,000
Litigation accrual	200,000,000	7,500,000
Other liabilities	11,726,000	16,520,000
Total liabilities	939,906,000	656,443,000
Redeemable common shares related to 401KSOP and Employee Stock Ownership Plan (ESOP) 8,499 and 9,188 shares at redemption value as of December 31, 2023 and 2022	188,680,000	169,978,000
Common shareholders' equity:
Common shares, $.50 par value, per share; 96,000 shares authorized; 77,328 and 76,640 shares issued and outstanding before deducting treasury shares and which excludes 8,499 and 9,188 shares subject to redemption as of December 31, 2023 and 2022	39,308,000	38,550,000
Additional paid-in capital	197,962,000	162,828,000
Common shares subscribed, unissued	22,832,000	23,864,000
Retained earnings	330,436,000	293,993,000
Accumulated other comprehensive loss	(4,785,000)	(5,588,000)
Stockholders' equity before treasury stock	585,753,000	513,647,000
Less: Cost of Common shares held in treasury; 44,480 shares in 2023 and 43,110 in 2022	416,616,000	363,502,000
Common shares subscription receivable	16,663,000	20,345,000
Total common shareholders' equity	152,474,000	129,800,000
Total liabilities and shareholders' equity	$ 1,281,060,000	$ 956,221,000
Redeemable stock, outstanding	8,499,086	9,188,010
Common stock, shares issued	77,328,434	76,639,510
Treasury stock, shares	44,480,126	43,110,036
Common stock, par value (in dollars per share)	$ 0.50	$ 0.50
Common stock, shares authorized	96,000,000	96,000,000