Credit Agreements 2016 Term Loan Agreement (Details) - USD ($) $ in Millions		3 Months Ended
	Feb. 10, 2016	Sep. 30, 2016	Dec. 31, 2016	Mar. 11, 2016	Jun. 12, 2015
Short-term Debt [Line Items]
Long-term Debt, Gross			$ 780.8		$ 7.1
2016 Credit Agreement [Member]
Short-term Debt [Line Items]
Long-term Debt			285.0
Senior Notes [Member] | 2016 Term Loan Agreement [Member]
Short-term Debt [Line Items]
Long-term Debt, Gross	$ 0.0
2016 Term Loan Agreement [Member]
Short-term Debt [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.75%
LIBOR Plus Margin [Member] | 2016 Credit Agreement [Member]
Short-term Debt [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.00%
LIBOR Plus Margin [Member] | 2016 Term Loan Agreement [Member]
Short-term Debt [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.75%
Term Loan [Member] | 2016 Credit Agreement [Member]
Short-term Debt [Line Items]
Long-term Debt			$ 392.5	$ 0.0