Benefit Plans - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available under the Stock Incentive Plan	1,900,000
Amortization related to restricted stock/Unit awards and LTIP Unit Awards	$ 8,611	$ 7,371	$ 7,177
Unrecognized compensation related to unvested restricted stock/Unit awards and LTIP Unit Awards	$ 7,752
Weighted average period of unrecognized compensation expected to be recognized	10 months 16 days
Matching contributions in 401(k)/profit sharing plan	$ 518	$ 509	$ 471
LTIP Unit Awards \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage of LTIP Unit Awards	0.00%
LTIP Unit Awards \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage of LTIP Unit Awards	100.00%
Management \| Restricted Stock/Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock/Unit Awards and LTIP Unit Awards issued	260,685	308,373	216,975
Fair Value of restricted stock/Unit awards and LTIP Unit Awards issued	$ 6,871	$ 6,047	$ 4,708
Vesting period of restricted stock/Unit awards and LTIP Unit Awards issued	3 years
Compensation expense recognized at date of grant	$ 1,590	$ 1,710	$ 1,352
Management \| LTIP Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock/Unit Awards and LTIP Unit Awards issued	195,951	254,524
Fair Value of restricted stock/Unit awards and LTIP Unit Awards issued	$ 2,473	$ 2,561
Vesting period of restricted stock/Unit awards and LTIP Unit Awards issued	3 years
Director \| Restricted Stock/Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock/Unit Awards and LTIP Unit Awards issued	15,108	14,460	17,385
Fair Value of restricted stock/Unit awards and LTIP Unit Awards issued	$ 420	$ 350	$ 350
Vesting period of restricted stock/Unit awards and LTIP Unit Awards issued	1 year

The fair value at approval date of non-option equity instruments granted during the period.

No definition available.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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-Publisher FASB
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Amount of contributions made by employer into fund established for purposes of making future disbursement to individual in accordance with deferred compensation arrangement.

+ References

No definition available.

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Unrecognized cost of unvested share-based compensation awards.

+ References

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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Additional share-based compensation cost recognized as a result of an occurrence of an event that accelerates its recognition.

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No definition available.

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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No definition available.

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Net number of non-option equity instruments granted to participants.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Percentage of vesting of share-based compensation awards.

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