Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost capitalized for award under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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Long-Term Incentive Plan (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Long-Term Incentive Plan (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Compensation expense and forfeitures
Capitalized compensation cost related to shares issued to design and construction employees			$ 201	$ 214
Restricted Shares
Compensation expense and forfeitures
Amortization Expense, including forfeitures	$ 2,900	$ 2,865	5,022	4,865
Capitalized compensation cost related to shares issued to design and construction employees	$ 100	$ 100	$ 200	$ 200
Restricted Shares \| Minimum
Long-Term Incentive Plan
Vesting period			3 years