Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities
Net income	$ 27,225	$ 26,259
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation, amortization and accretion	10,544	15,019
Amortization of debt related costs	959	1,031
Provision for bad debt	288	2
Provision for excess and obsolete inventory	2,470	1,002
Stock-based compensation	6,419	3,764
Loss on extinguishment of debt and debt retirement costs	0	2,161
Deferred taxes	7,220	0
Long-term income tax receivable	(2,220)	(1,345)
Long-term income tax payable and other long-term liabilities	2,397	2,120
Other	1,001	627
Increases (decreases) in cash from operating assets and liabilities:
Accounts receivable	(7,205)	(4,609)
Inventory	(9,832)	(6,361)
Other current assets	(49)	54
Accounts payable	2,200	(270)
Accrued expenses and other liabilities	2,470	2,237
Net cash provided by operating activities	43,887	41,691
Investing activities
Capital expenditures	(12,766)	(11,589)
Proceeds from sales of assets	1,000	1,234
Net cash used in investing activities	(11,766)	(10,355)
Financing activities
Proceeds from issuance of long-term debt	0	274,313
Payments on long-term debt	(2,146)	(285,979)
Deferred financing costs	0	(1,576)
Payments for public offering costs	0	(74)
Proceeds from stock option exercises	1,152	1,210
Proceeds from issuance of common stock	428	187
Payments for minimum statutory tax withholding related to net share settlement of equity awards	(3,168)	(2,681)
Net cash used in financing activities	(3,734)	(14,600)
Effect of foreign exchange rates on cash and cash equivalents	(93)	163
Net increase in cash and cash equivalents	28,294	16,899
Cash and cash equivalents, beginning of period	76,290	51,178
Cash and cash equivalents, end of period	$ 104,584	$ 68,077