Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 29, 2013	Mar. 30, 2012
Cash flows from operating activities:
Net income	$ 6,785	$ 6,118
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, depletion and amortization	8,572	11,951
Amortization of deferred financing costs in interest expense	162	157
Stock-based compensation expense	1,199	1,411
Changes in assets and liabilities net of acquired assets and liabilities:
Decrease (increase) in accounts receivable	(4,569)	(21,792)
Decrease (increase) in other receivables	314	2,473
Decrease (increase) in inventory	3,770	(1,381)
Decrease (increase) in prepaid and other current assets	2,390	(988)
Decrease (increase) in deferred income taxes	1,951	(1,295)
Increase (decrease) in accounts payable and accrued expenses	(26,153)	(19,527)
Increase (decrease) in unearned revenue	32	(784)
Increase (decrease) in interest and taxes payable	473	2,276
Increase (decrease) in long-term liabilities	(525)	(1,079)
Other-net	833	(512)
Net cash used in operating activities	(4,766)	(22,972)
Cash flows from investing activities:
Payments for purchase of property, plant and equipment	(5,781)	(9,282)
Payments for mine development	(3,874)	(159)
Reimbursements for capital equipment under government contracts	0	563
Payments for purchase of business net of cash received	0	(3,955)
Other investments-net	8	1,742
Net cash used in investing activities	(9,647)	(11,091)
Cash flows from financing activities:
Proceeds from issuance (repayments) of short-term debt	(678)	17,160
Proceeds from issuance of long-term debt	20,097	20,105
Repayment of long-term debt	(247)	(247)
Principal payments under capital lease obligations	(164)	(191)
Payment of dividends	(1,544)	0
Issuance of common stock under stock option plans	576	128
Tax benefit from stock compensation realization	920	67
Net cash provided from financing activities	18,960	37,022
Effects of exchange rate changes	(361)	(68)
Net change in cash and cash equivalents	4,186	2,891
Cash and cash equivalents at beginning of period	16,056	12,255
Cash and cash equivalents at end of period	$ 20,242	$ 15,146