Risk Management and Use of Derivative Financial Instruments (Details 7) In Thousands, unless otherwise specified	Dec. 31, 2014 USD ($)	Dec. 31, 2014 Designated as hedging Cash Flow Hedging Foreign currency contract EUR USD ($) instrument	Dec. 31, 2014 Designated as hedging Cash Flow Hedging Foreign currency contract EUR EUR (€)	Dec. 31, 2014 Designated as hedging Cash Flow Hedging Foreign currency contract JPY USD ($) instrument	Dec. 31, 2014 Designated as hedging Cash Flow Hedging Foreign currency contract JPY JPY (¥)	Dec. 31, 2014 Designated as hedging Cash Flow Hedging Foreign currency contract NOK USD ($) instrument	Dec. 31, 2014 Designated as hedging Cash Flow Hedging Foreign currency contract NOK	Dec. 31, 2014 Designated as hedging Net Investment Hedging Foreign currency contract JPY USD ($) instrument	Dec. 31, 2014 Designated as hedging Net Investment Hedging Foreign currency contract JPY JPY (¥)	Dec. 31, 2014 Designated as hedging Net Investment Hedging Foreign currency contract NOK USD ($) instrument	Dec. 31, 2014 Designated as hedging Net Investment Hedging Foreign currency contract NOK	Dec. 31, 2014 Not designated Foreign currency contract EUR USD ($) instrument	Dec. 31, 2014 Not designated Foreign currency contract EUR EUR (€)
Derivative Instrument Detail
Derivative number of instruments		97	97	12	12	17	17	1	1	5	5	2	2
Notional Amount			€ 195,354		¥ 563,608		12,239		¥ 610,129		7,996		€ 90,000
Fair value, foreign currency derivatives	$ 26,267	$ 19,479		$ 2,211		$ 16		$ 2,335		$ 10		$ 2,216