Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating Activities
Net income	$ 12,295	$ 21,569
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	3,797	4,164
Stock-based compensation	1,170	895
Deferred income taxes	352	(237)
Gain on disposal of property, plant and equipment	(37)	(67)
Excess tax benefits from stock compensation	(6,507)
Changes in operating assets and liabilities:
Accounts receivable	(79,152)	(90,840)
Inventories	(7,785)	2,487
Prepaid expenses and other assets	(82)	850
Accounts payable	(3,892)	1,874
Accrued expenses and other liabilities	(9,068)	(7,004)
Income taxes receivable/payable	6,884	356
Net cash used in operating activities	(82,025)	(65,953)
Investing Activities
Expenditures for property, plant and equipment	(3,188)	(1,910)
Proceeds from sales of property, plant and equipment	37	67
Purchase of acquired company, net of cash acquired	(44)
Notes receivable, net	19	31
Net cash used in investing activities	(3,176)	(1,812)
Financing Activities
Financing costs		(73)
Borrowings under line of credit	85,000	67,000
Principal payments under line of credit	(5,000)
Repurchases of common stock	(1,433)	(1,996)
Proceeds from employee stock purchase and option plans	84	2,577
Excess tax benefits from stock compensation	6,507
Net cash provided by financing activities	85,158	67,508
Net decrease in cash and cash equivalents	(43)	(257)
Cash and cash equivalents at beginning of period	3,772	2,159
Cash and cash equivalents at end of period	3,729	1,902
Supplemental Disclosure:
Cash paid for interest, net of capitalized interest	99	96
Cash paid for income taxes, net	$ 91	$ 79