SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for doubtful accounts, sales returns and cash discounts
Changes to valuation allowance
Balance at beginning of period	$ 1,870	$ 2,130	$ 992
Charged to cost and expenses	8,368	7,535	9,983
Deductions	(8,345)	(7,795)	(8,845)
Balance at end of period	1,893	1,870	2,130
Allowance on Deferred Tax Assets
Changes to valuation allowance
Balance at beginning of period	4,003	432
Charged to cost and expenses	3,589	3,571	432
Balance at end of period	$ 7,592	$ 4,003	$ 432