Stock-Based Compensation Stock-Based Compensation (Details) - USD ($) $ in Thousands, shares in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount	[1]	$ (1,119)	$ (2,325)	$ (3,509)
Stock-based compensation, net of capitalization		$ 13,581	14,339	13,635
Share-based compensation arrangement by share-based payment award, number of shares Authorized		5.4
Share-based compensation arrangement by share-based payment award, number of shares available for grant		4.7
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	[2]	$ 14,248	16,254	16,745
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Noninterest Expense Directors Fees		452	410	399
Parent Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, net of capitalization		$ 13,581	$ 14,339	$ 13,635

[1] Includes compensation expense specifically identifiable to development and redevelopment activities.  During 2018, these amounts also include compensation expense specifically identifiable to leasing activities, as non-contingent internal leasing costs were capitalizable prior to the adoption of Topic 842, Leases, on January 1, 2019

[2] Includes amortization of the grant date fair value of restricted stock awards over the respective vesting periods