Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash	$ 15,861	$ 19,647
Accounts receivable, net	105,256	115,563
Operating supplies	5,661	6,030
Prepaid expenses	11,393	9,101
Other current assets	13,845	11,408
Total current assets	152,016	161,749
Property and equipment:
Land and land improvements	13,904	13,213
Buildings and leasehold improvements	27,364	25,676
Equipment	442,882	412,790
Property and equipment	484,150	451,679
Less accumulated depreciation	347,266	325,963
Property and equipment, net	136,884	125,716
Other assets	16,917	14,284
Identified intangible assets and goodwill, net	27,561	29,183
Total assets	333,378	330,932
Current liabilities:
Short-term debt	8,434	6,992
Accounts payable	37,922	36,972
Accrued expenses	36,858	34,462
Self-insurance accruals	22,057	20,115
Total current liabilities	105,271	98,541
Long-term debt	20,034	24,787
Senior unsecured notes	30,000	30,000
Self-insurance accruals	34,655	41,618
Other liabilities	12,280	17,880
Total liabilities	202,240	212,826
Common shareholders' equity:
Common shares, $1.00 par value, per share; 24,000 shares authorized; 21,457 shares issued and outstanding before treasury shares as of December 31, 2013 and 2012	21,457	21,457
Additional paid-in capital	5,008	3,431
Common shares subscribed	10,467	11,055
Retained earnings	230,975	210,652
Accumulated other comprehensive income (loss)	(4,393)	(7,115)
Stockholders' equity before treasury stock	263,514	239,480
Less: Cost of Common shares held in treasury; 8,018 shares in 2013 and 7,731 in 2012	125,034	112,159
Common shares subscription receivable	7,342	9,215
Common shareholders' equity	131,138	118,106
Total liabilities and shareholders' equity	$ 333,378	$ 330,932