Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net loss	$ (5,736)	$ (1,952)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	23,333	21,269
Deferred financing amortization	301	529
Employee retirement benefits	(2,037)	1,410
Provision for uncollectible receivables	1,004	950
Stock based compensation	572	567
Deferred income taxes	(1,395)	(1,251)
Changes in operating assets and liabilities:
Receivables	55	1,050
Material and supplies	5	619
Prepaid expenses and other current assets	698	(217)
Accounts payable and accrued expenses	(947)	(3,162)
Advance billings and customer deposits	1,466	954
Other current liabilities	(51)	340
Other	(166)	(839)
Net cash provided by operating activities	17,102	20,267
Cash flows from investing activities:
Capital expenditures	(24,336)	(27,242)
Net cash used in investing activities	(24,336)	(27,242)
Cash flows from financing activities:
Proceeds from borrowing		6,000
Repayment of capital lease and installment financing	(9,056)	(1,051)
Repayment of borrowings	(4,563)	(750)
Refinancing costs		(2,071)
Taxes paid related to net share settlement of equity awards	(715)	(495)
Net cash provided by (used in) financing activities	(14,334)	1,633
Net change in cash, cash equivalents and restricted cash	(21,568)	(5,342)
Cash, cash equivalents and restricted cash, beginning of period	41,009	21,146
Cash, cash equivalents and restricted cash, end of period	$ 19,441	$ 15,804