Taxes - Additional Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Tax Credit Carryforward [Line Items]
Domestic income from continuing operations before taxes	$ 41,226,000	$ 29,576,000	$ 36,754,000
Foreign income from continuing operations before taxes	106,171,000	58,310,000	49,876,000
Increase (decrease) in tax expense for the final true-up of the prior year's tax accrual upon filing the actual tax returns	(674,000)	267,000	84,000
Increase (decrease) in tax expense upon the expiration of the statutes of limitation for certain reserves for income tax uncertainties	(217,000)	(1,790,000)	(441,000)
Income Tax Examination, Increase (Decrease) in Liability from Prior Year	(553,000)
Increase (decrease) in tax expense for release of tax reserves resulting from audit	(296,000)
Increase (decrease) in interest and penalties	(46,000)	(854,000)	(58,000)
Increase (decrease) in tax expense from write down of noncurrent deferred tax asset			101,000
Unrecognized tax benefit shown as a reduction to noncurrent deferred tax assets	1,028,000
Reserve for income taxes	4,623,000	4,765,000
Deferred Tax Liabilities, Gross, Noncurrent	5,651,000
Interest and penalties, gross	524,000	357,000
Minimum decrease in income tax expense due to release in reserves	900,000
Maximum decrease in income tax expense due to release in reserves	1,000,000
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals	342,000
Non deductible federal and state liabilities	2,430,000	3,662,000
Income from expiration of the statute of limitations relating to a tax		354,000	141,000
Income tax paid net	17,549,000	8,831,000	13,551,000
Open Tax Year State Authorities	2011 through 2013
Open tax year United States Internal Revenue Service	2012 through 2013
Tax years open to examination, various authorities	2010 through 2013
Tax years covered through Advanced Pricing Agreement		2006 through 2011
Tax years in negotiation for APA agreement	Between 2014 and 2018
State research and experimentation tax carryforwards	2014 through 2016
Research and Development tax credit [Member]
Tax Credit Carryforward [Line Items]
Reduction in tax expense	757,000	555,000
Research Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Valuation Allowance	725,000
State Research And Experimentation [Member]
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Research	$ 5,575,000