Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash	$ 19,647	$ 10,267
Accounts receivable, net	115,563	90,795
Operating supplies	6,030	5,586
Prepaid expenses	9,101	6,968
Other current assets	11,408	16,920
Total current assets	161,749	130,536
Property and equipment:
Land and land improvements	13,213	13,221
Buildings and leasehold improvements	25,676	25,311
Equipment	412,790	400,457
Property and equipment	451,679	438,989
Less accumulated depreciation	325,963	308,841
Property and equipment, net	125,716	130,148
Other assets	14,284	15,969
Identified intangible assets and goodwill, net	29,183	27,081
Total assets	330,932	303,734
Current liabilities:
Short-term debt	6,992	5,837
Accounts payable	36,972	35,282
Accrued expenses	34,462	34,123
Self-insurance accruals	20,115	26,793
Total current liabilities	98,541	102,035
Long-term debt	24,787	21,136
Senior unsecured notes	30,000	30,000
Self-insurance accruals	41,618	30,472
Other liabilities	17,880	19,365
Total liabilities	212,826	203,008
Common shareholders' equity:
Common shares, $1.00 par value, per share; 24,000 shares authorized; 21,457 shares issued and outstanding as of December 31, 2012 and 2011	21,457	21,457
Additional paid-in capital	3,431	1,721
Common shares subscribed	11,055	0
Retained earnings	210,652	188,613
Accumulated other comprehensive income (loss)	(7,115)	(6,344)
Stockholders' equity before treasury stock	239,480	205,447
Less: Cost of Common shares held in treasury; 7,731 shares in 2012 and 7,611 in 2011	112,159	104,721
Common shares subscription receivable	9,215	0
Common shareholders' equity	118,106	100,726
Total liabilities and shareholders' equity	$ 330,932	$ 303,734