Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash	$ 12,483	$ 13,121
Accounts receivable, net	178,269	168,671
Operating supplies	13,922	10,069
Other current assets	12,326	17,264
Total current assets	217,000	209,125
Property and equipment	640,087	616,036
Less accumulated depreciation	431,851	422,853
Property and equipment, net	208,236	193,183
Other assets	24,874	29,156
Identified intangible assets and goodwill, net	43,144	41,671
Total assets	493,254	473,135
Current liabilities:
Accounts payable	37,076	45,093
Accrued expenses	40,512	42,816
Other current liabilities	33,959	40,748
Total current liabilities	111,547	128,657
Long-term debt	157,907	119,210
Self-insurance accruals	45,093	43,912
Other noncurrent liabilities	17,040	19,966
Total liabilities	331,587	311,745
Redeemable common shares related to 401KSOP and Employee Stock Ownership Plan (ESOP); 6,169 and 6,467 shares at redemption value as of June 30, 2018 and December 31, 2017	121,525	123,520
Common shareholders' equity:
Common shares, $1.00 par value, per share; 48,000 shares authorized; 36,745 and 36,447 shares issued and outstanding before deducting treasury shares and which excludes 6,169 and 6,467 shares subject to redemption as of June 30, 2018 and December 31, 2017	36,745	36,447
Additional paid-in capital	69,810	58,554
Common shares subscribed, unissued	7,131	7,529
Retained earnings	153,647	143,835
Accumulated other comprehensive loss	(9,679)	(8,393)
Shareholders' equity before treasury stock	257,654	237,972
Less: Cost of common shares held in treasury; 19,290 shares at June 30, 2018 and 18,693 shares at December 31, 2017	216,065	198,327
Common shares subscription receivable	1,447	1,775
Total common shareholders' equity	40,142	37,870
Total liabilities and shareholders' equity	$ 493,254	$ 473,135