Risk Management and Use of Derivative Financial Instruments - Narratives (Details) - USD ($)	6 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Derivative Instrument Detail
Derivative asset collateral offset	$ 0	$ 0
Derivative, remaining maturity	77 months
Collateral received	$ 0
Total credit exposure on derivatives	14,200,000
Derivatives, net liability position	3,500,000	5,600,000
Aggregate termination value for immediate settlement	3,600,000	$ 5,700,000
Single Counterparty
Derivative Instrument Detail
Total credit exposure on derivatives	8,200,000
Interest expense
Derivative Instrument Detail
Estimated amount reclassified from OCI to income, derivatives	500,000
Other gains and (losses)
Derivative Instrument Detail
Estimated amount reclassified from OCI to income, derivatives	$ (7,100,000)

The aggregate fair value of assets needed to immediately settle the derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

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-SubTopic 10
-Section 50
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Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions.

+ References

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Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

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Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets.

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The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

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Period remaining until the derivative contract matures, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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