Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 12,551	$ 10,267
Accounts receivable, net	92,849	90,795
Operating supplies	6,558	5,586
Other current assets	20,197	23,888
Total current assets	132,155	130,536
Property and equipment	449,571	438,989
Less accumulated depreciation	315,316	308,841
Property and equipment, net	134,255	130,148
Other assets	16,826	15,969
Identified intangible assets and goodwill, net	26,662	27,081
Total assets	309,898	303,734
Current liabilities:
Accounts payable	35,303	35,282
Accrued expenses	25,995	34,123
Other current liabilities	30,919	32,630
Total current liabilities	92,217	102,035
Long-term debt	67,101	51,136
Self-insurance accruals	33,414	30,472
Other noncurrent liabilities	15,250	19,365
Total liabilities	207,982	203,008
Common shareholders' equity:
Common shares, $1.00 par value, per share; 24,000 shares authorized; 21,457 shares issued	21,457	21,457
Additional paid-in capital	2,633	1,721
Retained earnings	187,448	188,613
Accumulated other comprehensive loss	(5,611)	(6,344)
Stockholders' Equity before Treasury Stock	205,927	205,447
Less: Cost of Common shares held in treasury; 7,505 shares at March 31, 2012 and 7,611 shares at December 31, 2011	104,011	104,721
Stockholders' Equity Attributable to Parent	101,916	100,726
Total liabilities and shareholders' equity	$ 309,898	$ 303,734