Executive Deferred Compensation Plan (Details) - Executive [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Executive Deferred Compensation Plan [Abstract]
Percentage of matching contribution maximum	10.00%
Percentage of compensation deferred, maximum	80.00%
Percentage of bonus deferred, maximum	100.00%
Percentage vested after ten years of service	50.00%
Number of years of service to attain fifty percent vesting	10 years
Percentage vested per year after ten years of service	5.00%
Minimum age for unvested company contributions to fully vest	60 years
Compensation expense	$ 2.3	$ 0.3	$ 3.1
Long-term deferred compensation liability	33.5	32.4
Investment in Rabbi Trust	$ 27.3	$ 26.3