Derivative Financial Instruments - Free-Standing (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2016 shares	Dec. 31, 2019 USD ($)	Oct. 31, 2019 USD ($)	Sep. 27, 2019	Jun. 30, 2019	Jul. 31, 2018 USD ($)	Jun. 28, 2018	Dec. 31, 2017
Minimum
Derivative financial instruments
Derivative, Floating rate	0.99%
Maximum
Derivative financial instruments
Derivative, Floating rate	7.83%
Visa | Class B restricted shares
Derivative financial instruments
Estimated liability that was subsequently paid to the buyer					$ 300,000
Number of shares sold | shares			274,000
Funding Swap (Visa Derivative)
Derivative financial instruments
Derivative liability value	$ 3,200,000			$ 4,200,000
Funding Swap (Visa Derivative) | Class B restricted shares
Derivative financial instruments
Conversion rate						1.6228	1.6298		1.6298	1.6483
Funding Swap (Visa Derivative) | Visa
Derivative financial instruments
Estimated liability that was subsequently paid to the buyer					$ 300,000			$ 700,000
Derivatives Not Designated as Hedging Instruments | Interest rate swaps
Derivative financial instruments
Notional Amount	2,901,085,000			$ 2,818,803,000
Net interest expense on derivative	$ 0	$ 0
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Minimum
Derivative financial instruments
Fixed interest rate (as a percent)	2.02%			1.71%
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Maximum
Derivative financial instruments
Fixed interest rate (as a percent)	8.73%			8.73%
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Customer swap program
Derivative financial instruments
Notional Amount	$ 2,900,000,000
Positive fair value, derivative asset	158,700,000			$ 63,500,000
Negative fair value, derivative liability	0			0
Upfront fees on the dealer swap	1,900,000	$ 800,000
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Included in other assets
Derivative financial instruments
Positive fair value, derivative asset	158,711,000			63,527,000
Derivatives Not Designated as Hedging Instruments | Funding Swap (Visa Derivative)
Derivative financial instruments
Notional Amount	85,645,000			82,900,000
Derivatives Not Designated as Hedging Instruments | Funding Swap (Visa Derivative) | Included in other liabilities
Derivative financial instruments
Negative fair value, derivative liability	$ 3,199,000			$ 4,233,000