Acquisitions and Divestitures - Sale of operating property - (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Acquisitions and Divestitures
Loan carrying value	$ 13,238,408,000		$ 12,217,352,000
Unpaid principal balance	13,301,495,000		12,262,840,000
Allowance	72,284,000		$ 77,444,000
Proceeds from sale of operating properties		$ 0
Operating properties | Commercial and Residential Lending Segment
Acquisitions and Divestitures
Loan carrying value	9,000,000.0
Unpaid principal balance	20,900,000
Allowance	8,300,000
Unamortized discount	3,600,000
Proceeds from sale of operating properties	30,600,000
Gain on sale of property	$ 17,700,000