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 Doubtful Accounts [Member]
Beginning of Period	$ 2,564		$ 3,409		$ 3,219
Charged to Costs and Expenses	1,784		266		2,035
Charged to Other Accounts	1,119	[1]	1,468	[1]	0	[1]
Deductions	1,584	[2]	2,579	[2]	1,845	[2]
Balance at End of Period	3,883		2,564		3,409
Allowance for Returns [Member]
Beginning of Period	1,361		850		1,617
Charged to Costs and Expenses	0		0		0
Charged to Other Accounts	10,742	[3]	5,542	[3]	2,427	[3]
Deductions	9,539	[4]	5,031	[4]	3,194	[4]
Balance at End of Period	2,564		1,361		850
Valuation Allowance for Deferred Tax Assets [Member]
Beginning of Period	9,235		13,999		8,680
Charged to Costs and Expenses	0		0		0
Charged to Other Accounts	8,950	[5]	(4,764)	[6]	5,319	[6]
Deductions	0		0		0
Balance at End of Period	$ 18,185		$ 9,235		$ 13,999

[1] Adjustments from acquisitions.

[2] Uncollectible accounts written off, net of recoveries.

[3] Charged against revenues.

[4] Credits issued for returns.

[5] Related to deferred tax assets on foreign tax credits, net operating loss carryforwards, and depreciation.

[6] Related to deferred tax assets on unrealized losses and acquisitions.