Income Taxes Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business Acquisition
Effective income tax rate					32.60%	34.80%
Net Income	$ 122,688	$ 142,785	$ 112,171	$ 101,346	$ 377,644	$ 328,163
All 2016 Acquisitions
Business Acquisition
Deferred Tax Assets, Other	29,700				29,700
Deferred Tax Liabilities, Other	137,500				137,500
ASU 2016-09 adjustments [Member] | Restatement Adjustment [Member]
Business Acquisition
Net Income	$ 4,984	$ 2,048	$ 4,439		$ 11,471