Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Statement of Financial Position [Abstract]
Cash and cash equivalents	$ 232,028	$ 258,825	$ 233,587
Trade accounts receivable, net	135,123	106,011	117,316
Inventories	210,787	195,757	205,312
Deferred income taxes	0	16,203	12,666
Other current assets	13,284	12,476	19,565
Total current assets	591,222	589,272	588,446
Property, plant and equipment, net	216,660	213,716	205,009
Goodwill	125,614	123,950	122,923
Intangible assets, net	26,719	27,675	31,484
Other noncurrent assets	8,746	6,696	4,797
Total assets	968,961	961,309	952,659
Trade accounts payable	29,023	21,309	21,456
Accrued liabilities	49,849	54,761	46,261
Income taxes payable	2,824	0	0
Accrued profit sharing trust contributions	2,245	5,799	1,960
Accrued cash profit sharing and commissions	11,133	8,502	7,131
Accrued workers’ compensation	4,472	4,593	4,479
Total current liabilities	99,546	94,964	81,287
Deferred income tax and other long-term liabilities	5,159	16,521	16,082
Total liabilities	$ 104,705	$ 111,485	$ 97,369
Commitments and contingencies (Note 7)
Common stock, at par value	$ 484	$ 481	$ 493
Additional paid-in capital	238,040	238,212	226,007
Retained earnings	648,321	639,707	652,298
Treasury stock	(3,502)	0	0
Accumulated other comprehensive income (loss)	(19,087)	(28,576)	(23,508)
Total stockholders’ equity	864,256	849,824	855,290
Total liabilities and stockholders’ equity	$ 968,961	$ 961,309	$ 952,659