INCOME TAXES (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income before income tax expense
U.S. operations	$ 59,478	$ 67,379	$ 32,123
Foreign operations	18,858	21,447	8,724
Income before income tax expense	78,336	88,826	40,847
Current:
Federal	16,766	16,794	1,488
State	3,240	3,561	1,426
Foreign	3,936	7,900	2,834
Total current:	23,942	28,255	5,748
Deferred
Federal	2,934	4,087	7,044
State	608	695	420
Foreign	851	(2,222)	(389)
Total deferred	4,393	2,560	7,075
Income tax expense	28,335	30,815	12,823
Deferred tax assets
Accounts receivable, principally due to allowance for doubtful accounts	1,986	1,514
Inventories	3,340	2,762
Net operating loss carryforwards	8,433	8,888
Accrued pension	31,544	26,924
Stock-based compensation	4,966	7,343
Compensation-related accruals	3,209	3,103
Warranty	2,781	3,459
Obligation for postretirement benefits other than pension	4,187	4,467
Accrued liabilities and other items	4,755	4,037
Gross deferred tax assets	65,201	62,497
Valuation allowance	(7,798)	(7,385)
Net deferred tax assets	57,403	55,112
Deferred tax liabilities:
Intangibles	84,518	82,841
Plant and equipment	11,206	11,361
Gross deferred tax liabilities	95,724	94,202
Net deferred tax liabilities	$ (38,321)	$ (39,090)