Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Income tax provision as percentage of income before taxes	6.10%		10.60%
Tax benefits recognized due to a lapse of the statute of limitations	$ 775,000			$ 661,000
Income tax provision, foreign filing			424,000
Benefit for 2012 research tax credits			1,400,000
Percentage of income before taxes		22.30%		30.60%
Tax benefits recognized due to settlements with taxing authorities				176,000
Liability for uncertain tax positions	11,800,000		11,800,000
Net liability, reduced for the federal effects of potential state tax exposures	8,400,000		8,400,000
Tax provision, included not yet reduced income tax payments	5,400,000		5,400,000
Anticipated significant change to uncertain income tax positions accrued in current and long term taxes payable	3,000,000		3,000,000
Long-term uncertain income tax positions within the next 12 months	2,897,000		2,897,000
Accrued Income Taxes, Current	103,000		103,000
Interest and penalties related to income tax	310,000		310,000		354,000
Current deferred tax assets	22,400,000		22,400,000
Net long-term deferred tax assets	586,000		586,000
Deferred tax valuation allowance	$ 8,500,000		$ 8,500,000