Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net income	$ 26,259	$ 21,893
Adjustments to reconcile net income to net cash flows from operating activities
Depreciation, amortization and accretion	15,019	12,664
Amortization of debt related costs	1,031	1,235
Provision for excess and obsolete inventory	1,002	982
Stock-based compensation	3,764	1,869
Gain on sales of assets	0	(6,505)
Loss on extinguishment of debt and debt retirement costs	2,161	1,415
Other	1,404	(254)
Increases (decreases) in cash from operating assets and liabilities
Accounts receivable	(4,609)	1,071
Inventory	(6,361)	(1,658)
Other current assets	54	(1,032)
Accounts payable	(270)	2,684
Accrued expenses and other liabilities	2,237	2,497
Net cash provided by operating activities	41,691	36,861
Investing activities
Proceeds from sales of assets	1,234	10,541
Capital expenditures	(11,589)	(4,976)
Other	0	74
Net cash (used in) provided by investing activities	(10,355)	5,639
Financing activities
Payments on long-term debt	(285,979)	(57,790)
Proceeds from issuance of long-term debt	274,313	0
Proceeds from issuance of common stock	187	41,600
Payments for public offering costs	0	(1,266)
Proceeds from stock option exercises	1,210	61
Payments for minimum statutory tax withholding related to net share settlement of equity awards	(2,681)	(552)
Deferred financing costs	(1,576)	(11)
Other	(74)	0
Net cash used in financing activities	(14,600)	(17,958)
Effect of foreign exchange rates on cash and cash equivalents	163	57
Net increase in cash and cash equivalents	16,899	24,599
Cash and cash equivalents, beginning of period	51,178	28,596
Cash and cash equivalents, end of period	$ 68,077	$ 53,195