Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Product warranty and recall at beginning of period	$ 6,107	$ 5,301
Accruals for products shipped during period	2,215	594
Aggregate changes in pre-existing liabilities due to claim developments	1,229	251
Settlements made during the period (in cash or in kind)	(3,369)	(1,313)
Product warranty and recall at end of period	$ 6,182	$ 4,833