Employee Benefit Plans, 401(k) plan and Deferred Compensation Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Benefit Textuals [Abstract]
Employee Contribution Matched in Percent	30.00%
Matching Contributions to Plan	$ 20.7	$ 19.6	$ 20.2
NQDC [Member]
Employee Benefit Textuals [Abstract]
Deferred compensation liability, noncurrent	$ 21.0
Deferred compensation liability, current		$ 17.7