SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION - Analysis of Carrying Amount of Real Estate Properties and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Real Estate Properties
Additions	$ 6,300	$ 11,600	$ 13,900
Balance at the end of the year	406,102
Accumulated Depreciation
Balance at the beginning of the year	143,319	202,700	375,968
Additions	15,054	15,275	22,697
Disposals	(1,934)	(74,656)	(195,965)
Balance at the end of the year	156,439	143,319	202,700
Aggregate cost of properties for federal income tax purposes	393,423
Real Estate Properties
Real Estate Properties
Balance at the beginning of the year	401,710	662,121	1,139,642
Additions	6,326	11,642	13,895
Disposals	(1,934)	(272,053)	(491,416)
Balance at the end of the year	$ 406,102	$ 401,710	$ 662,121
Buildings and improvements | Maximum
Accumulated Depreciation
Estimated useful lives	40 years
Personal property | Maximum
Accumulated Depreciation
Estimated useful lives	12 years