Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	6 Months Ended
	Jul. 01, 2011	Jul. 02, 2010
Consolidated Statements of Cash Flows [Abstract]
Net income	$ 25,690	$ 20,440
Adjustment to reconcile net income to net cash provided from operating activities:
Depreciation, depletion and amortization	22,425	17,100
Amortization of deferred financing costs in interest expense	233	282
Derivative financial instrument ineffectiveness		489
Stock-based compensation expense	2,191	1,988
Changes in assets and liabilities net of acquired assets and liabilities:
Decrease (increase) in accounts receivable	(8,627)	(58,366)
Decrease (increase) in other receivables	1,293	6,229
Decrease (increase) in inventory	(26,805)	(10,276)
Decrease (increase) in prepaid and other current assets	(5,561)	(1,147)
Decrease (increase) in deferred income taxes	(200)	6,117
Increase (decrease) in accounts payable and accrued expenses	(6,415)	(1,798)
Increase (decrease) in unearned revenue	454	(29)
Increase (decrease) in interest and taxes payable	(4,346)	(359)
Increase (decrease) in long-term liabilities	(1,655)	(1,265)
Other - net	(5,814)	(59)
Net cash used in operating activities	(7,137)	(20,654)
Cash flows from investing activities:
Payments for purchase of property, plant and equipment	(11,103)	(24,768)
Payments for mine development	(183)	(7,425)
Reimbursements for capital equipment under government contracts	2,570	14,915
Payments for purchase of business net of cash received		(20,605)
Proceeds from transfer of acquired inventory to consignment line		5,667
Proceeds from sale of property, plant and equipment	33	76
Other investments - net	13	14
Net cash used in investing activities	(8,670)	(32,126)
Cash flows from financing activities:
Repayment of short-term debt	(8,522)	(14,035)
Proceeds from issuance of long-term debt	42,472	70,000
Repayment of long-term debt	(25,083)
Debt issuance costs	(623)
Principal payments under capital lease obligations	(441)	(55)
Issuance of common stock under stock option plans	698	851
Tax benefit from stock compensation realization	376	164
Net cash provided from financing activities	8,877	56,925
Effects of exchange rate changes	287	(317)
Net change in cash and cash equivalents	(6,643)	3,828
Cash and cash equivalents at beginning of period	16,104	12,253
Cash and cash equivalents at end of period	$ 9,461	$ 16,081