Other Assets - Summary of Mortgage Revenue Bonds and Total Funding Commitment (Parenthetical) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Mortgage Revenue Bonds [Line Items]
Tax exempt loan maturity periods	6 months
Mortgage Revenue Bonds [Member] | Ocotillo Springs [Member] | Series A-T [Member]
Mortgage Revenue Bonds [Line Items]
Tax exempt loan maturity periods		1 year
MRB Partnership Advances	$ 1.0		$ 0.0