Summary of Deferred Income Taxes Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current deferred tax assets (liabilities):
Accounts receivable	$ 202	$ 306
Inventories	3,265	3,318
Warranty costs	2,302	1,874
Foreign exchange contracts	(58)	(157)
Accrued benefits	1,993	1,945
Other accruals not currently deductible for tax purposes	1,044	1,453
Deferred Tax Assets, Gross, Current, Total	8,748	8,739
Valuation allowance	(568)	(532)
Net current deferred tax assets	8,180	8,207
Noncurrent deferred tax (liabilities) assets:
Amortization and fixed assets	8,516	13,620
Pension obligation	4,913	8,828
Net operating loss carryforwards	27,613	18,365
Tax credit carryforwards	1,823	1,631
Stock options	410	608
Other temporary differences not currently available for tax purposes	(2,617)	(2,478)
Deferred Tax Assets, Gross, Noncurrent, Total	40,658	40,574
Valuation allowance	(16,621)	(16,960)
Net noncurrent deferred tax assets	24,037	23,614
Total deferred tax asset	$ 32,217	$ 31,821