Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income (loss)	$ (5,429)	$ 1,599
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	43,012	44,443
Deferred financing amortization	888	1,005
Loss on early extinguishment of debt	4,826
Employee retirement benefits	(420)	(3,896)
Provision for uncollectible receivables	1,788	2,139
Stock based compensation	1,273	1,141
Deferred income taxes	(3,506)	1,377
Changes in operating assets and liabilities:
Receivables	3,559	1,477
Material and supplies	963	(104)
Prepaid expenses and other current assets	(1,868)	(2,594)
Accounts payable and accrued expenses	(3,579)	6,837
Advance billings and customer deposits	82	(1,593)
Other current liabilities	648	(385)
Other	(1,681)	(157)
Net cash provided by operating activities	40,556	51,289
Cash flows from investing activities:
Capital expenditures	(52,630)	(52,898)
Net cash used in investing activities	(52,630)	(52,898)
Cash flows from financing activities:
Proceeds from borrowing	330,000
Proceeds from installment financing	1,260	1,698
Repayment of capital lease and installment financing	(2,225)	(1,707)
Repayment of borrowings	(300,138)	(1,500)
Refinancing costs	(6,295)	(688)
Taxes paid related to net share settlement of equity awards	(495)	(351)
Net cash provided by (used in) financing activities	22,107	(2,548)
Net change in cash, cash equivalents and restricted cash	10,033	(4,157)
Cash, cash equivalents and restricted cash, beginning of period	21,146	34,137
Cash, cash equivalents and restricted cash, end of period	$ 31,179	$ 29,980