Debt And Lines Of Credit , Narrative - Aspen Preferred OP Units and Series B-3 preferred OP units (Details)	1 Months Ended	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($) Rate	Mar. 31, 2020 USD ($) Rate	Jun. 30, 2021 USD ($) shares	Jun. 30, 2020 USD ($) Rate	Dec. 31, 2020 USD ($) shares $ / shares Rate	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2015 $ / shares
Debt Instrument [Line Items]
Convertible units to shares (in shares) | shares							1,013,819
Financial Instruments Subject to Mandatory Redemption, Rate Of Return	6.00%
Gain (Loss) on Extinguishment of Debt		$ (8,108,000)	$ (1,930,000)		$ (8,108,000)	$ (5,209,000)
Preferred Equity, Mandatorily Redeemable [Member]
Debt Instrument [Line Items]
Financial Instruments Subject to Mandatory Redemption, Value of Shares Issued								$ 33,400,000	$ 35,300,000
Preferred OP units - mandatorily redeemable		35,249,000			35,249,000		$ 35,249,000
Temporary Equity, Term								7 years
Preferred OP units [Member]
Debt Instrument [Line Items]
Convertible units to shares (in shares) | shares							270,000
Debt Instrument, Interest Rate During Period | Rate							6.50%
Preferred OP units - mandatorily redeemable							$ 34,663,000
Preferred OP units [Member] | Convertible debt - Aspen Preferred OP Units January 2024 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 34,700,000			$ 34,700,000		$ 34,700,000
Convertible units to shares (in shares) | shares					394,814
Debt Instrument, Interest Rate During Period | Rate							3.80%
Debt Instrument, Convertible, Conversion Price | $ / shares							$ 27.00			$ 68.00
Debt Instrument, Convertible, Percent Of Amount By Which The Market Price Of Common Stock Exceeds Threshold | Rate							25.00%
Conversion of Stock, Shares Converted | shares							0.397
Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount				$ 230,000,000			$ 268,800,000
Secured Debt [Member] | Matures December 1, 2021, 5.98 Percent Interest Rate
Debt Instrument [Line Items]
Reduction in secured borrowing balance			$ 52,710,000		$ 0
Interest rate | Rate			5.98%			5.98%
Gain (Loss) on Extinguishment of Debt			$ 1,930,000
Secured Debt [Member] | Matures March 1, 2021, 5.837 Percent Interest Rate [Member] [Domain] [Domain]
Debt Instrument [Line Items]
Reduction in secured borrowing balance				$ 99,607,000
Interest rate | Rate				5.837%
Gain (Loss) on Extinguishment of Debt				$ 3,403,000
Secured Debt [Member] | Matures July 1, 2020, 5.86 Percent Interest Rate [Member] [Domain]
Debt Instrument [Line Items]
Reduction in secured borrowing balance				$ 19,922,000
Interest rate | Rate				5.83%
Gain (Loss) on Extinguishment of Debt				$ (124,000)