Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 7,202	$ 10,267
Accounts receivable, net	106,280	90,795
Operating supplies	7,063	5,586
Other current assets	17,429	23,888
Total current assets	137,974	130,536
Property and equipment	448,945	438,989
Less accumulated depreciation	317,128	308,841
Property and equipment, net	131,817	130,148
Other assets	16,663	15,969
Identified intangible assets and goodwill, net	26,198	27,081
Total assets	312,652	303,734
Current liabilities:
Accounts payable	33,101	35,282
Accrued expenses	32,936	34,123
Other current liabilities	28,115	32,630
Total current liabilities	94,152	102,035
Long-term debt	58,917	51,136
Self-insurance accruals	36,799	30,472
Other noncurrent liabilities	15,529	19,365
Common shareholders' equity:
Common shares, $1.00 par value, per share; 24,000 shares authorized; 21,457 shares issued	21,457	21,457
Total liabilities	205,397	203,008
Additional paid-in capital	3,089	1,721
Retained earnings	196,216	188,613
Accumulated other comprehensive loss	(5,846)	(6,344)
Stockholders' Equity before Treasury Stock	214,916	205,447
Less: Cost of Common shares held in treasury; 7,644 shares at June 30, 2012 and 7,611 shares at December 31, 2011	107,661	104,721
Stockholders' Equity Attributable to Parent	107,255	100,726
Total liabilities and shareholders' equity	$ 312,652	$ 303,734