Accounts payable, accrued expenses, and tenant security deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accounts payable and accrued expenses	$ 198,994		$ 215,539
Accrued Construction	275,818		275,882
Acquired below-market leases	194,773		134,808
Conditional asset retirement obligation	14,037		10,343
Deferred rent liabilities	2,897		29,547
Interest rate hedge liabilities	0		768
Operating lease liability	271,808	$ 218,700	0
Unearned rent and tenant security deposits	275,863		250,923
Other liabilities	86,078		63,897
Accounts Payable and Accrued Liabilities	$ 1,320,268		$ 981,707