Valuation and Qualifying Accounts and Reserves (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for doubtful accounts [Member]
VALUATION AND QUALIFYING ACCOUNTS AND RESERVES
Valuation and Qualifying Accounts and Reserves, Beginning Balance	$ 292	$ 335	$ 1,457
Additions (Reductions) Charged to Cost and Expenses	(362)	23	(185)
Other	0	0	0
Deductions	77	(66)	(937)
Valuation and Qualifying Accounts and Reserves, Ending Balance	7	292	335
Warranty Reserves [Member]
VALUATION AND QUALIFYING ACCOUNTS AND RESERVES
Valuation and Qualifying Accounts and Reserves, Beginning Balance	16,345	14,472	11,524
Additions (Reductions) Charged to Cost and Expenses	21,487	9,976	14,960
Other	0	0	0
Deductions	(8,845)	(8,103)	(12,012)
Valuation and Qualifying Accounts and Reserves, Ending Balance	28,987	16,345	14,472
Income tax valuation allowance [Member]
VALUATION AND QUALIFYING ACCOUNTS AND RESERVES
Valuation and Qualifying Accounts and Reserves, Beginning Balance	24,199	21,090	15,218
Additions (Reductions) Charged to Cost and Expenses	(68)	3,109	5,872
Other	0	0	0
Deductions	0	0	0
Valuation and Qualifying Accounts and Reserves, Ending Balance	$ 24,131	$ 24,199	$ 21,090