Basis of Presentation and Summary of Significant Accounting Policies (Recent Accounting Pronouncements) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Excess tax benefit amount		$ 7,400
Stock-based compensation expenses	$ 2,865		$ 2,238		$ 5,247	$ 5,986
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock-based compensation expenses				$ 600
Accounting Standards Update 2016-09 [Member] | Additional Paid-in Capital [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption				$ 600