Covenants and Events of Default (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Debt Instrument [Line Items]
Covenant Compliance	We were in compliance with the covenants contained in our senior note agreements and Credit Agreement.
Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	215.0
Letter of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	100.0