Employee Benefit Benefits and Stock-Based Compensation - Annual Discretionary Bonus Grant (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2013
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Defined Contribution Plan, Maximum Annual Contribution Per Employee		$ 18,000
Restricted Stock Unit Bonus Grant
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted or Expected to Be Granted in Next Fiscal Period			1.4
Subsequent Event [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Defined Contribution Plan, Maximum Annual Contribution Per Employee	$ 18,000