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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into equity in earnings of unconsolidated joint ventures on derivative instruments designated and qualifying as hedging instruments.

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Represents the amount of adjustments for nonperformance risk included in termination liability.

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Amount of gain or loss excluded from effectiveness testing on the cash flow hedges.

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Number of interest rate swaps as the forecasted hedged transactions were no longer probable of occurring.

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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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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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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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Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Fair Value Measurements - Derivative Instruments, Gain (Loss) (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) item	Sep. 30, 2017 USD ($) item	Dec. 31, 2017 USD ($)
Reclassification of gain (loss)
Amount of reclassification from Accumulated other comprehensive income to earnings			$ 110,000
Interest rate swap \| Cash flow hedges
Fair Value Measurements
Amount of gain (loss) recognized on derivatives in Other comprehensive income	$ 827,000	$ (248,000)	4,336,000	$ (1,234,000)
Amount of reclassification from Accumulated other comprehensive income into Interest expense	(44,000)	(352,000)	(335,000)	(1,406,000)
Reclassification of gain (loss)
Amount of reclassification from Accumulated other comprehensive income to earnings			110,000	118,000
Amount of effectiveness testing on cash flow hedges	0	0	0	$ 0
Additional amount to be reclassified during the next twelve months			$ 503,000
Number of interest rate swaps \| item			2	2
Credit risk related contingent feature
Accrued interest on derivative in a liability position					$ 53,000
Fair value of derivative in a liability position, including accrued interest but excluding adjustments for nonperformance risk					1,638,000
Termination value of derivative agreement					1,638,000
Derivatives in liability position	$ 0		$ 0
Interest rate swap \| Cash flow hedges \| Accrued expenses and other liabilities
Credit risk related contingent feature
Adjustments for nonperformance risk					$ 93,000
Unconsolidated joint ventures \| Interest rate swap \| Cash flow hedges
Fair Value Measurements
Amount of gain (loss) recognized on derivatives in Other comprehensive income		(2,000)	69,000	$ (14,000)
Amount of reclassification from Accumulated other comprehensive income into Equity in earnings of unconsolidated joint ventures		$ (13,000)	$ 103,000	$ (48,000)