XML 37 R62.htm IDEA: XBRL DOCUMENT v2.4.0.8
Fair value measurements (Details) (USD $)
Dec. 31, 2013
Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Derivative instruments, current liability $ 0 $ 714,000
Debt instrument, carrying value 513,075,000 420,705,000
Senior secured revolving credit facility [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt instrument, carrying value 108,000,000 122,480,000
Senior unsecured notes due October 2021 [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt instrument, carrying value 403,208,000 0
Senior unsecured notes due October 2021 [Member] | Significant other observable inputs (Level 2) [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt instrument, fair value 419,300,000  
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Notional amount $ 75,000,000.0  
Fixed interest rate 1.83%