Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale, net	$ 91.1	$ 58.5
Unpaid principal balance	$ 222.3	191.3
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short term borrowings maturity period	30 days
Fair Value, Inputs, Level 2 | Under Commitment to Sell
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale, net	$ 137.3	136.8
Fair Value, Inputs, Level 2 | Not Under Commitment to Sell
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale, net	$ 95.3	$ 60.2