Condensed Consolidated Balance Sheets - USD ($) $ in Thousands		Jul. 01, 2017	Dec. 31, 2016
Current assets:
Cash		$ 9,683	$ 9,006
Accounts receivable, net		157,555	146,134
Operating supplies		10,878	7,277
Other current assets		9,644	16,356
Total current assets		187,760	178,773
Property and equipment		608,435	588,650
Less accumulated depreciation		409,677	409,214
Property and equipment, net		198,758	179,436
Other assets		32,299	31,354
Identified intangible assets and goodwill, net		41,355	34,376
Total assets		460,172	423,939
Current liabilities:
Accounts payable		38,507	41,283
Accrued expenses		37,622	37,659
Other current liabilities		33,071	39,963
Total current liabilities		109,200	118,905
Long-term debt		129,296	92,290
Self-insurance accruals		44,955	39,746
Other noncurrent liabilities		19,552	20,819
Total liabilities		303,003	271,760
Redeemable common shares related to 401KSOP and Employee Stock Ownership Plan (ESOP)		123,169	124,201
Common shareholders' equity:
Common shares, $1.00 par value, per share; 48,000 shares authorized; 42,914 shares issued and outstanding before deducting treasury shares as of July 1, 2017 and December 31, 2016	[1]	36,183	35,857
Additional paid-in capital	[1]	52,514	41,626
Common shares subscribed, unissued		7,920	8,209
Retained earnings	[1]	138,468	133,951
Accumulated other comprehensive loss		(10,645)	(12,162)
Shareholders' equity before treasury stock		224,440	207,481
Less: Cost of common shares held in treasury; 18,336 shares at July 1, 2017 and 17,991 shares at December 31, 2016		187,888	176,530
Common shares subscription receivable		2,552	2,973
Common shareholders' equity		34,000	27,978
Total liabilities and shareholders' equity		$ 460,172	$ 423,939

[1] Adjusted for two-for-one stock split