Pension and Other Postretirement Benefit Plans (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Non-cash postretirement benefits curtailment and settlement gain	$ 0	$ 0	$ (45.0)
Benefit obligation period increase	4.9
Estimated future employer contributions in next fiscal year	0.3
Defined contribution retirement plan expense	0.8	2.2	2.4
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-cash postretirement benefits curtailment and settlement gain	0	0	0
Future amortization of net gain (loss)	2.1
Future amortization of net prior service cost (credit)	(0.1)
Settlements	(0.3)	(1.6)
Curtailments	0	(3.8)
Reclassification adjustment	0	0
Accumulated benefit obligation	172.6	160.9
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-cash postretirement benefits curtailment and settlement gain	0	0	(45.0)
Settlements	0	0
Curtailments	0	0
Reclassification adjustment	$ 0	$ 0.3