Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Defined Contribution Plan, Employer Matching Contribution, Percent of Match			100.00%
Defined Contribution Plan, Contributions by Employee			3.00%
Pension Plan [Member]
Defined Benefit Plan, Service Cost	$ 1.4	$ 1.6	$ 4.1	$ 4.8
Defined Benefit Plan, Interest Cost	1.8	2.1	5.5	6.4
Defined Benefit Plan, Expected Return on Plan Assets	(2.4)	(2.6)	(7.4)	(7.6)
Defined Benefit Plan, Amortization of Gains (Losses)	1.7	1.7	4.6	5.2
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	2.0	0.0	2.0	0.0
Defined Benefit Plan, Net Periodic Benefit Cost	4.5	2.8	8.8	8.8
Other Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Service Cost	0.4	0.3	1.3	0.9
Defined Benefit Plan, Interest Cost	0.1	0.1	0.3	0.3
Defined Benefit Plan, Net Periodic Benefit Cost	$ 0.5	$ 0.4	$ 1.6	$ 1.2
50% [Domain]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match			50.00%
2% [Domain]
Defined Contribution Plan, Contributions by Employee			2.00%