Debt (Details) (Line of Credit [Member], USD $)
Sep. 30, 2014
Aug. 12, 2014
Line of Credit Facility [Line Items]    
Line of credit facility, available borrowing capacity $ 248,600,000  
Revolving Credit Facility [Member]
   
Line of Credit Facility [Line Items]    
Line of credit facility, maximum principle amount   250,000,000
Line of credit facility, additional borrowing capacity   250,000,000
Line of credit facility, borrowings outstanding 0  
Standby Letters of Credit [Member]
   
Line of Credit Facility [Line Items]    
Line of credit facility, maximum principle amount   40,000,000
Line of credit facility, borrowings outstanding 1,400,000  
Swing Line Loan [Member]
   
Line of Credit Facility [Line Items]    
Line of credit facility, maximum principle amount   $ 25,000,000