Financial Instruments: Derivatives and Hedging (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Financial Instruments: Derivatives and Hedging
Fair Value	$ 26,132,000		$ 26,132,000
Gain (loss) from changes in fair value	100,000	$ 0	(300,000)	$ 100,000
Fair value of derivatives in a net liability position	0		0
Aggregate termination value	0		0
Estimated current balance held in accumulated other comprehensive loss to be reclassified into earnings within the next 12 months			2,600,000
Share of joint venture of accumulated other comprehensive loss reclassified into equity in net income from unconsolidated joint ventures within the next 12 months			1,400,000
Amount of Gain (Loss) Recognized in Other Comprehensive Loss (Effective Portion)	4,208,000	(3,364,000)	14,803,000	(6,160,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	231,000	(811,000)	(99,000)	(2,189,000)
Amount of Gain (Loss) Recognized into Income (Ineffective Portion)	(33,000)	34,000	(131,000)	(69,000)
Interest Rate Swap Expiring in July 2023
Financial Instruments: Derivatives and Hedging
Notional Value	$ 200,000,000		$ 200,000,000
Strike Rate	1.131%		1.131%
Fair Value	$ 15,272,000		$ 15,272,000
Interest Rate Swap Expiring in July 2023
Financial Instruments: Derivatives and Hedging
Notional Value	$ 100,000,000		$ 100,000,000
Strike Rate	1.161%		1.161%
Fair Value	$ 7,496,000		$ 7,496,000
Interest Rate Cap Expiring September 2019
Financial Instruments: Derivatives and Hedging
Notional Value	$ 137,500,000		$ 137,500,000
Strike Rate	4.00%		4.00%
Fair Value	$ 1,000		$ 1,000
Interest Rate Swap Expiring November 2020
Financial Instruments: Derivatives and Hedging
Notional Value	$ 100,000,000		$ 100,000,000
Strike Rate	1.928%		1.928%
Fair Value	$ 1,688,000		$ 1,688,000
Interest Rate Swap Expiring November 2020, 2
Financial Instruments: Derivatives and Hedging
Notional Value	$ 100,000,000		$ 100,000,000
Strike Rate	1.934%		1.934%
Fair Value	$ 1,675,000		$ 1,675,000
Interest Rate Swaps/Caps
Financial Instruments: Derivatives and Hedging
Amount of Gain (Loss) Recognized in Other Comprehensive Loss (Effective Portion)	3,116,000	(2,036,000)	10,398,000	(5,173,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	76,000	(519,000)	(253,000)	(1,498,000)
Amount of Gain (Loss) Recognized into Income (Ineffective Portion)	(3,000)	0	(12,000)	(8,000)
Joint venture
Financial Instruments: Derivatives and Hedging
Amount of Gain (Loss) Recognized in Other Comprehensive Loss (Effective Portion)	1,092,000	(1,328,000)	4,405,000	(987,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	155,000	(292,000)	154,000	(691,000)
Amount of Gain (Loss) Recognized into Income (Ineffective Portion)	$ (30,000)	$ 34,000	$ (119,000)	$ (61,000)

Accumulated Other Comprehensive Income (Loss), Gain (Loss) from Changes in Fair Value

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Represents the estimated net amount of existing gains (losses) on cash flow hedges at the reporting date expected to be reclassified to equity in net income within the next 12 months.

+ References

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- Definition

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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
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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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- Definition

Nominal or face amount used to calculate payments on the derivative asset.

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

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- Definition

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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- 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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- Definition

The net gain (loss) during the reporting period due to ineffectiveness in interest rate cash flow hedges. Recognized in earnings.

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- Definition

The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

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- Definition

Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

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