Supplemental Cash Flow Information of the Company - Supplemental Cash Flow (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Jan. 01, 2019
SUPPLEMENTAL CASH FLOWS INFORMATION:
Cash paid for interest, net of capitalized interest of $39,952 and $38,780 as of June 30, 2020 and 2019, respectively	$ 25,494	$ 23,009
Capitalized interest	39,952	38,780
Cash paid for amounts included in the measurement of ground lease liabilities	2,905	2,699
NON-CASH INVESTING TRANSACTIONS:
Accrual for expenditures for operating properties and development properties	131,892	129,500
Tenant improvements funded directly by tenants	7,210	7,017
Initial measurement of operating right of use ground lease assets	95,940		$ 96,348	$ 82,938
Initial measurement of operating ground lease liabilities	98,093		$ 98,400	$ 87,409
NON-CASH FINANCING TRANSACTIONS:
Accrual of dividends and distributions payable to common stockholders and common unitholders (Note 15)	57,600	50,800
Exchange of common units of the Operating Partnership into shares of the Company’s common stock	$ 3,843	$ 78