Unaudited 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	$ 86,772	$ 73,957
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	5,298	4,435
Amortization of debt issuance costs	74	61
Stock-based compensation	2,135	2,065
Loss on disposal of fixed assets	562	13
Deferred income taxes	2,402	12,721
Tax benefit from exercise of stock options	0	(36)
Payment of legal settlement	0	(32,000)
Effect of changes in operating assets and liabilities:
Receivables	(15,773)	(4,212)
Inventories	(18,525)	(3,923)
Prepaid expenses and other assets	(1,002)	(334)
Accounts payable	15,415	2,741
Other liabilities	(14,318)	(835)
Net cash provided by operating activities	63,040	54,653
Cash flows from investing activities:
Capital expenditures	(32,937)	(3,766)
Net cash used in investing activities	(32,937)	(3,766)
Cash flows from financing activities:
Proceeds from borrowings of new debt	400,000	0
Repayment of long-term debt	(382,147)	0
Payments related to long-term refinancing	(4,382)	0
Principal payments on long-term debt	(990)	(1,980)
Tax benefit from exercise of stock options	0	36
Proceeds from exercise of stock options	3,292	373
Net cash provided by (used in) financing activities	15,773	(1,571)
Effect of exchange rate changes on cash and cash equivalents	198	(14)
Net increase in cash and cash equivalents	46,074	49,302
Cash and cash equivalents at beginning of period	292,656	224,253
Cash and cash equivalents at end of period	$ 338,730	$ 273,555