Long-Term Debt - Narrative (Details) (USD $) In Millions, unless otherwise specified		3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 Six Point Zero Percent Senior Notes Due On June Fifteen Two Thousand And Seventeen [Member]	May 08, 2013 Six Point Zero Percent Senior Notes Due On June Fifteen Two Thousand And Seventeen [Member]	Mar. 31, 2014 Miles Kimball [Member]	Dec. 31, 2013 Miles Kimball [Member]
Debt Instrument [Line Items]
Note issuance date		May 10, 2013
Senior notes issued			$ 50.0
Interest rate of Senior Notes			6.00%
Maturity date of long-term debt outstanding		Jun. 30, 2017
Long-term debt outstanding				5.4	5.5
Long-term debt fixed interest rate				7.89%
Amount available under uncommitted bank facility to be used for letters of credit	2.4
Letters of credit outstanding, amount	$ 1.1