Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Aggregate product warranty liability [Roll Forward]
Beginning balance	$ 4,847,000	$ 3,620,000
Claims paid or accrued	(4,714,000)	(3,032,000)
Additional warranties issued	5,404,000	4,225,000
Revisions in estimates	624,000	67,000
Foreign currency translation	21,000	(33,000)
Ending balance	6,182,000	4,847,000	3,620,000
Future minimum rental payments for operating leases [Abstract]
2013	8,694,000
2014	7,368,000
2015	5,006,000
2016	3,642,000
2017	2,191,000
Thereafter	3,353,000
Expense for rentals and leases [Abstract]
Expense for rentals and leases	14,200,000	9,900,000	7,800,000
Contractual commitments for capital expenditures [Abstract]
Contractual commitments for capital expenditures expected to be paid in next fiscal year	$ 30,800,000