Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for Bad Debts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 1,183	$ 1,066	$ 1,175
Charged to costs and expenses	530	3,935	397
Charged to other accounts	0	0	0
Deductions	(510)	(3,818)	(506)
Balance at end of period	1,203	1,183	1,066
Sales Returns and Allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	4,097	3,980	3,356
Charged to costs and expenses	317	291	721
Charged to other accounts	0	0	0
Deductions	(805)	(174)	(97)
Balance at end of period	3,609	4,097	3,980
Deferred Tax Asset Valuation Allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	0	226	1,058
Charged to costs and expenses	0	0	226
Charged to other accounts	0	0	0
Deductions	0	(226)	(1,058)
Balance at end of period	$ 0	$ 0	$ 226