Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Statement of Financial Position [Abstract]
Cash and cash equivalents	$ 242,795	$ 260,307	$ 258,238
Trade accounts receivable, net	132,727	92,015	127,495
Inventories	200,282	216,545	198,420
Deferred income taxes	14,782	14,662	13,141
Other current assets	10,302	20,789	12,985
Total current assets	600,888	604,318	610,279
Property, plant and equipment, net	202,885	207,027	206,134
Goodwill	123,277	123,881	125,228
Intangible assets, net	28,570	32,587	34,782
Other noncurrent assets	4,426	5,252	5,420
Total assets	960,046	973,065	981,843
Line of credit and notes payable	0	18	38
Trade accounts payable	24,934	22,860	24,729
Accrued liabilities	52,881	56,078	56,913
Income taxes payable	2,000	0	0
Accrued profit sharing trust contributions	4,383	5,384	4,663
Accrued cash profit sharing and commissions	12,566	6,039	13,721
Accrued workers’ compensation	4,486	4,101	4,432
Total current liabilities	101,250	94,480	104,496
Deferred income tax and other long-term liabilities	14,415	15,120	13,224
Total liabilities	$ 115,665	$ 109,600	$ 117,720
Commitments and contingencies (Note 7)
Common stock, at par value	$ 493	$ 489	$ 490
Additional paid-in capital	225,788	220,982	217,011
Retained earnings	679,673	649,174	648,608
Treasury stock	(39,529)	0	(2,981)
Accumulated other comprehensive income (loss)	(22,044)	(7,180)	995
Total stockholders’ equity	844,381	863,465	864,123
Total liabilities and stockholders’ equity	$ 960,046	$ 973,065	$ 981,843