Income Taxes (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income tax provision as percentage of income before taxes	35.40%	19.10%		33.90%	12.20%
Effective income tax rate reconciliation, foreign income tax rate differential, amount		$ 400,000
Income tax benefit research and development tax credit			1,400,000
Unrecognized tax benefits for uncertain tax positions	13,600,000			13,600,000
Net amount, reduced for the federal effects of potential state tax exposures	9,800,000			9,800,000
Net amount, favorably affect the company's tax provision in future periods	3,900,000			3,900,000
Increase in deferred tax assets, uncertain tax positions	5,900,000			5,900,000
Liability for uncertain tax positions in long term taxes payable	3,771,000			3,771,000		3,575,000
Accrued income taxes, current, in income taxes payable	100,000			100,000
Interest and penalties related to income tax	400,000			400,000		400,000
Current deferred tax assets, net	24,100,000			24,100,000
Deferred tax liabilities, net, noncurrent	1,500,000			1,500,000
Deferred tax valuation allowance	9,700,000			9,700,000		9,000,000
State and Local Jurisdiction [Member]
Deferred Tax Assets, Tax Credit Carryforwards, Research	23,500,000			23,500,000
Deferred tax Assets, Tax Carryforwards, Research, Pre-Ownership Change	$ 2,300,000			$ 2,300,000