Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income	$ 154	$ 975
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	21,950	21,280
Deferred financing amortization	492	472
Employee retirement benefits	(1,846)	(1,952)
Provision for uncollectible receivables	1,039	1,248
Stock based compensation	579	375
Deferred income taxes	240	837
Changes in operating assets and liabilities:
Receivables	207	(943)
Material and supplies	(1,417)	(91)
Prepaid expenses and other current assets	(1,249)	(121)
Accounts payable and accrued expenses	965	(3,782)
Advance billings and customer deposits	592	484
Other current liabilities	(278)	(185)
Other	(512)	336
Net cash provided by operating activities	20,916	18,933
Cash flows from investing activities:
Capital expenditures	(28,139)	(29,172)
Net cash used in investing activities	(28,139)	(29,172)
Cash flows from financing activities:
Repayment of debt	(750)	(750)
Proceeds from installment financing		354
Repayment of capital lease and installment financing	(1,135)	(1,382)
Taxes paid related to net share settlement of equity awards	(352)	(928)
Net cash used in financing activities	(2,237)	(2,706)
Net change in cash and cash equivalents	(9,460)	(12,945)
Cash and cash equivalents, beginning of period	30,312	39,885
Cash and cash equivalents, end of period	20,852	26,940
Supplemental disclosure of cash flow information:
Interest paid, net of amounts capitalized	$ 2,492	$ 3,953