Noncontrolling Interests (Narrative) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) property shares	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Noncontrolling Interests [Line Items]
Common units in operating partnership | shares			7,305,355
Noncontrolling interests	$ 218,618,000		$ 218,618,000		$ 216,135,000
Number of Units in Multi-Family Asset | property			395
Number of shares of common stock for each unit of limited partnership interest redeemed | shares	1		1
Net income allocation to noncontrolling interests - common units	$ 6,782,000	$ 7,613,000	$ 17,857,000	$ 14,637,000
Net (income) loss allocated to Noncontrolling interest - joint venture	13,000	10,000	30,000	13,000
Distribution paid	25,000	$ 45,000	63,000	$ 45,000
PS [Member]
Noncontrolling Interests [Line Items]
Noncontrolling interests	215,700,000		215,700,000		213,200,000
JV Partner [Member]
Noncontrolling Interests [Line Items]
Noncontrolling interests	$ 2,900,000		$ 2,900,000		$ 2,900,000
Consolidated entity ownership percentage	5.00%		5.00%