Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jul. 02, 2016	Dec. 31, 2015
Current assets:
Cash	$ 13,366	$ 16,030
Accounts receivable, net	140,817	120,001
Operating supplies	7,495	7,171
Other current assets	10,141	17,732
Total current assets	171,819	160,934
Property and equipment	594,857	557,194
Less accumulated depreciation	409,398	390,772
Property and equipment, net	185,459	166,422
Other assets	33,996	31,949
Identified intangible assets and goodwill, net	34,870	34,281
Total assets	426,144	393,586
Current liabilities:
Accounts payable	34,765	37,750
Accrued expenses	32,854	36,146
Other current liabilities	34,346	38,054
Total current liabilities	101,965	111,950
Long-term debt	115,708	84,633
Self-insurance accruals	42,158	37,786
Other noncurrent liabilities	17,251	17,678
Total liabilities	277,082	252,047
Common shareholders' equity:
Common shares, $1.00 par value, per share; 48,000 shares authorized; 21,457 shares issued and outstanding before deducting treasury shares as of July 2, 2016 and December 31, 2015	21,457	21,457
Additional paid-in capital	20,868	17,815
Common shares subscribed, unissued	8,350	8,591
Retained earnings	278,410	270,605
Accumulated other comprehensive loss	(10,889)	(13,394)
Shareholders' equity before treasury stock	318,196	305,074
Less: Cost of common shares held in treasury; 8,731 shares at July 2, 2016 and 8,714 shares at December 31, 2015	165,399	159,429
Common shares subscription receivable	3,735	4,106
Common shareholders' equity	149,062	141,539
Total liabilities and shareholders' equity	$ 426,144	$ 393,586