Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2019	Mar. 30, 2018
Cash flows from operating activities:
Net income	$ 16,906	$ 10,564
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation, depletion, and amortization	9,067	9,207
Amortization of deferred financing costs in interest expense	236	261
Stock-based compensation expense (non-cash)	1,547	771
Deferred income tax expense (benefit)	371	(359)
Changes in assets and liabilities:
Decrease (increase) in accounts receivable	(14,698)	(8,582)
Decrease (increase) in inventory	(9,561)	5,097
Decrease (increase) in prepaid and other current assets	(556)	(634)
Increase (decrease) in accounts payable and accrued expenses	(16,030)	(16,308)
Increase (decrease) in interest and taxes payable	2,525	1,626
Domestic pension plan contributions	(1,500)	(9,000)
Other-net	(924)	(818)
Net cash used in operating activities	(12,617)	(8,175)
Cash flows from investing activities:
Payments for purchase of property, plant, and equipment	(8,027)	(7,867)
Payments for mine development	(1,352)	(1,661)
Proceeds from sale of property, plant, and equipment	58	3
Net cash used in investing activities	(9,321)	(9,525)
Cash flows from financing activities:
Repayment of long-term debt	(197)	(190)
Principal payments under finance lease obligations	298	211
Cash dividends paid	(2,125)	(2,012)
Repurchase of common stock	(199)	0
Payments of withholding taxes for stock-based compensation awards	(3,978)	(2,133)
Net cash used in financing activities	(6,797)	(4,546)
Effects of exchange rate changes	(46)	608
Net change in cash and cash equivalents	(28,781)	(21,638)
Cash and cash equivalents at beginning of period	70,645	41,844
Cash and cash equivalents at end of period	$ 41,864	$ 20,206