Mortgage notes receivable - Additional Information (Details)	2 Months Ended	3 Months Ended			10 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) loan	Mar. 31, 2019 USD ($)		Nov. 14, 2019	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Loans and Leases Receivable Disclosure [Line Items]
Financial Designation, Predecessor and Successor [Fixed List]	Successor	Successor	Predecessor	[1]	Predecessor		Predecessor
Percentage of maximum loan to value ratio		65.00%
Percentage of maximum of amount of a single loan		10.00%
Percentage of assets of entity		15.00%
Carrying value for mortgage notes receivable	$ 821,589,000	$ 782,752,000				$ 821,589,000
Allowance for loan losses	4,096,000	$ 7,182,000	$ 1,480,000			4,096,000	$ 1,704,000
Monthly interest rate payment term		10 days
Impaired Financing Receivable, Interest Income, Cash Basis Method		$ 0
Impaired Financing Receivable, Recorded Investment	32,900,000	$ 152,200,000				32,900,000
Impaired Financing Receivable, Number Of Loans | loan		4
Impaired Financing Receivable, Unpaid Principal Balance		$ 31,700,000
Impaired Financing Receivable, Average Recorded Investment		$ 82,300,000				10,600,000
Maximum
Loans and Leases Receivable Disclosure [Line Items]
Interest rate (as a percent)		13.00%
Term of mortgage notes receivable		12 months
Minimum
Loans and Leases Receivable Disclosure [Line Items]
Interest rate (as a percent)		10.00%
Term of mortgage notes receivable		5 months
Mortgage notes receivables
Loans and Leases Receivable Disclosure [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 28,800,000	$ 145,000,000				$ 28,800,000

[1] Predecessor periods are combined as disclosed in Note 1.