Risk Management and Use of Derivative Financial Instruments - Foreign Currency Derivatives Details (Details)
€ in Thousands, ¥ in Thousands, NOK in Thousands, $ in Thousands
Dec. 31, 2016
USD ($)
instrument
Dec. 31, 2016
JPY (¥)
instrument
Dec. 31, 2016
NOK
instrument
Dec. 31, 2016
EUR (€)
instrument
Derivative Instrument Detail        
Fair value, foreign currency derivatives $ 39,253      
Cash Flow Hedging | Designated as hedging | Foreign currency forward contracts | Euro        
Derivative Instrument Detail        
Derivative number of instruments | instrument 61 61 61 61
Derivative notional amount | €       € 122,794
Fair value, foreign currency derivatives $ 35,199      
Cash Flow Hedging | Designated as hedging | Foreign currency forward contracts | NOK        
Derivative Instrument Detail        
Derivative number of instruments | instrument 13 13 13 13
Derivative notional amount | NOK     NOK 9,389  
Fair value, foreign currency derivatives $ 181      
Cash Flow Hedging | Designated as hedging | Foreign currency collars | Euro        
Derivative Instrument Detail        
Derivative number of instruments | instrument 2 2 2 2
Derivative notional amount | €       € 15,100
Fair value, foreign currency derivatives $ 522      
Cash Flow Hedging | Designated as hedging | Foreign currency collars | NOK        
Derivative Instrument Detail        
Derivative number of instruments | instrument 3 3 3 3
Derivative notional amount | NOK     NOK 2,000  
Fair value, foreign currency derivatives $ (2)      
Net Investment Hedging | Designated as hedging | Foreign currency forward contracts | NOK        
Derivative Instrument Detail        
Derivative number of instruments | instrument 3 3 3 3
Derivative notional amount | NOK     NOK 5,549  
Fair value, foreign currency derivatives $ 107      
Net Investment Hedging | Designated as hedging | Foreign currency forward contracts | JPY        
Derivative Instrument Detail        
Derivative number of instruments | instrument 5 5 5 5
Derivative notional amount | ¥   ¥ 806,679    
Fair value, foreign currency derivatives $ 3,248      
Net Investment Hedging | Designated as hedging | Foreign currency collars | NOK        
Derivative Instrument Detail        
Derivative number of instruments | instrument 1 1 1 1
Derivative notional amount | NOK     NOK 2,500  
Fair value, foreign currency derivatives $ (2)