Schedule II-Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 1,256	$ 1,335	$ 1,481
Additions	277	43	(21)
Deductions	(278)	(122)	(125)
Balance at end of year	1,255	1,256	1,335
Allowance For Sales Returns And Product Warranty [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	63,690	58,206	50,786
Additions	104,810	100,806	86,310
Deductions	(102,279)	(95,322)	(78,890)
Balance at end of year	66,221	63,690	58,206
Allowance For Price Protection [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	1,783	3,930	3,147
Additions	8,352	9,925	15,688
Deductions	(5,862)	(12,072)	(14,905)
Balance at end of year	$ 4,273	$ 1,783	$ 3,930