Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities
Net income	$ 46,681	$ 36,268
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	7,417	7,322
Deferred income taxes		(589)
Stock-based compensation	2,945	2,717
Gain on disposal of property, plant and equipment	(204)	(3)
Excess tax benefits from stock compensation	(810)	(1,771)
Other non-cash adjustments	(285)	(270)
Changes in operating assets and liabilities:
Accounts receivable	(48,268)	(88,074)
Inventories	4,348	5,121
Prepaid expenses and other assets	(67)	979
Accounts payable	(161)	(104)
Accrued expenses and other liabilities	(7,901)	(856)
Income taxes receivable/payable	11,937	11,360
Net cash provided by (used in) operating activities	15,632	(27,900)
Investing Activities
Expenditures for property, plant and equipment	(5,182)	(14,088)
Proceeds from sales of property, plant and equipment	4,349	3
Purchase of acquired company, net of cash acquired		(31)
Net cash used in investing activities	(833)	(14,116)
Financing Activities
Borrowings under line of credit	194,000	118,000
Principal payments under line of credit	(158,000)	(80,500)
Repurchases of common stock	(54,703)	(2,847)
Financing costs	(485)
Proceeds from employee stock purchase and option plans	137	197
Excess tax benefits from stock compensation	810	1,771
Net cash (used in) provided by financing activities	(18,241)	36,621
Net decrease in cash and cash equivalents	(3,442)	(5,395)
Cash and cash equivalents, beginning of period	5,995	9,544
Cash and cash equivalents, end of period	2,553	4,149
Supplemental Disclosure:
Cash paid for interest	696	284
Cash paid for income taxes, net	$ 13,982	$ 10,342