Basis of Presentation and Significant Accounting Policies Basis of Presentation and Significant Accounting Policies (Details) - USD ($) shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effective income tax rate reconciliation, excess tax benefit, amount	$ 1.2		$ 5.4
Increased in diluted weighted average common shares outstanding (in shares)	1,061	815	989	835
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increased in diluted weighted average common shares outstanding (in shares)	198		174