Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Current assets
Cash and cash equivalents	$ 155,035	$ 168,514	$ 140,950
Trade accounts receivable, net	211,179	135,958	172,331
Inventories	258,180	252,996	265,293
Other current assets	15,772	26,473	17,765
Total current assets	640,166	583,941	596,339
Property, plant and equipment, net	269,127	273,020	261,362
Goodwill	136,398	137,140	137,160
Equity investment (see Note 9)	2,528	2,549	2,595
Intangible assets, net	26,761	29,326	30,804
Other noncurrent assets	10,907	11,547	13,217
Total Assets	1,085,887	1,037,523	1,041,477
Current liabilities
Capital lease obligations - current portion	1,072	1,055	525
Trade accounts payable	47,985	31,536	37,742
Accrued liabilities	99,359	87,430	77,598
Accrued profit sharing trust contributions	4,681	7,054	4,146
Accrued cash profit sharing and commissions	14,895	9,416	14,245
Total current liabilities	167,992	136,491	134,256
Capital lease obligations - net of current portion	2,154	2,607	1,477
Deferred income tax and other long-term liabilities	11,939	13,647	6,333
Total liabilities	182,085	152,745	142,066
Commitments and contingencies (see Note 11)
Stockholders’ equity
Common stock, at par value	462	473	475
Additional paid-in capital	271,735	260,157	260,350
Retained Earnings	652,124	676,644	675,151
Treasury stock	(440)	(40,000)	(17,544)
Accumulated other comprehensive loss	(20,079)	(12,496)	(19,021)
Total stockholders’ equity	903,802	884,778	899,411
Total liabilities and stockholders’ equity	$ 1,085,887	$ 1,037,523	$ 1,041,477