Real Estate (Real Estate and Accumulated Depreciation) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cost
Balance, beginning of year		$ 1,527,478,000	$ 1,515,206,000
Properties transferred to held for sale		(184,639,000)	(22,512,000)	$ (36,265,000)
Outparcel dispositions		(387,000)	(840,000)
Property impairments		(83,224,000)
Improvements and betterments		29,296,000	35,624,000	37,089,000
Balance, end of the year		1,288,524,000	1,527,478,000	1,515,206,000
Accumulated depreciation
Balance, beginning of the year		428,569,000	389,861,000
Properties transferred held for sale		(55,165,000)	(3,947,000)	(10,143,000)
Outparcel dispositions			(90,000)
Depreciation expense	[1]	36,338,000	42,745,000	41,142,000
Balance, end of the year		409,742,000	428,569,000	389,861,000
Net book value		$ 878,782,000	$ 1,098,909,000	$ 1,125,345,000

[1] Depreciation is provided over the estimated useful lives of the buildings and improvements, which range from 3 to 40 years.