Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ (1,952)	$ 154
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	21,269	21,950
Deferred financing amortization	529	492
Employee retirement benefits	1,410	(1,846)
Provision for uncollectible receivables	950	1,039
Stock based compensation	567	579
Deferred income taxes	(1,251)	240
Changes in operating assets and liabilities:
Receivables	1,050	207
Material and supplies	619	(1,417)
Prepaid expenses and other current assets	(217)	(1,249)
Accounts payable and accrued expenses	(3,162)	965
Advance billings and customer deposits	954	592
Other current liabilities	340	(278)
Other	(839)	(512)
Net cash provided by operating activities	20,267	20,916
Cash flows from investing activities:
Capital expenditures	(27,242)	(28,139)
Net cash used in investing activities	(27,242)	(28,139)
Cash flows from financing activities:
Proceeds from borrowing	6,000
Repayment of capital lease and installment financing	(1,051)	(1,135)
Repayment of debt	(750)	(750)
Refinancing costs	(2,071)
Taxes paid related to net share settlement of equity awards	(495)	(352)
Net cash provided by (used in) financing activities	1,633	(2,237)
Net change in cash, cash equivalents and restricted cash	(5,342)	(9,460)
Cash, cash equivalents and restricted cash, beginning of period	21,146	34,137
Cash, cash equivalents and restricted cash, end of period	$ 15,804	$ 24,677