Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment in retained earnings, net of tax				$ 55
Income tax benefits	$ 10,300		$ 7,120	20,849	$ 15,909
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment in retained earnings, net of tax				(95)
Additional Paid-in-Capital [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment in retained earnings, net of tax				$ 150
Income tax benefits		$ 209