Other Accrued Liabilities, Sales returns liability Rollforward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Sales returns liability roll forward [Abstract]
Balance at beginning of year	$ 16,046	$ 11,781
Additions that reduce net sales	9,899	10,008
Deductions from reserves	(16,172)	(10,241)
Balance at end of period	$ 9,773	$ 11,548