Short-Term Borrowings (Details) - USD ($) $ in Millions		1 Months Ended
	Oct. 30, 2015	Oct. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Nov. 30, 2012
Revolving Credit Facility [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Debt instrument, term	5 years
BANK OF AMERICA - MERRILL LYNCH ATS [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding			$ 3.2
TD Bank [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding				$ 0.4
Credit Agreement [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Proceeds from lines of credit		$ 30.7
Credit Agreement [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowings outstanding			$ 3.0
Debt Instrument, Interest Rate, Effective Percentage			1.72%
Credit Agreement [Member] | BANK OF AMERICA - MERRILL LYNCH ATS [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity					$ 75.0
Overdraft facility					$ 5.0
Credit Agreement [Member] | BANK OF AMERICA - MERRILL LYNCH ATS [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowings outstanding				1.3
Letters of credit outstanding				3.2
Remaining borrowing capacity			$ 39.2	$ 70.5
October 2015 Line of Credit [Member] | Revolving Credit Facility [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 150.0