Summary of Significant Accounting Policies (Details Textuals) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Deferred Tax Assets, Net of Valuation Allowance, Current	$ 70,940		$ 70,940		$ 67,483
Deferred Tax Liabilities, Net, Current	22,912		22,912		$ 22,435
Summary of Significant Accounting Policies (Textuals) [Abstract]
Amortization expense	1,700	$ 1,600	3,500	$ 3,100
Future Amortization Expense Current Year			6,800
Aggregate amortization expense for 2016	6,500		6,500
Aggregate amortization expense for 2017	6,200		6,200
Aggregate amortization expense for 2018	5,900		5,900
Aggregate amortization expense for 2019	5,600		5,600
Aggregate amortization expense for 2020	5,300		5,300
Purchased Intangible Amortization, Gross	1,500	1,400	3,200	2,800
Purchased intangible amortization, net of tax	1,000	900	2,100	1,900
Amortization expense associated with capitalized software	6,900	6,000	$ 13,400	11,900
Standard Warranty Period			one
Share - based compensation expense	$ 3,600	$ 3,500	$ 7,200	$ 7,000