XML 26 R52.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value Information - Additional Information (Detail) (USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]    
Fair value assets transfers from Level 1 to Level 2 0us-gaap_FairValueAssetsLevel1ToLevel2TransfersAmount $ 0us-gaap_FairValueAssetsLevel1ToLevel2TransfersAmount
Fair value assets transfers from Level 2 to Level 1 0us-gaap_FairValueAssetsLevel2ToLevel1TransfersAmount $ 0us-gaap_FairValueAssetsLevel2ToLevel1TransfersAmount
Minimum [Member]    
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]    
Term of interest rate swap contracts by the counterparty, years 3 years  
Maximum [Member]    
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]    
Term of interest rate swap contracts by the counterparty, years 30 years