Derivatives - Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jul. 31, 2017
Derivatives, Fair Value [Line Items]
Notional Amount			$ 100,000
Not designated as hedging
Derivatives, Fair Value [Line Items]
Notional Amount	$ 3,112,743	$ 3,532,227
Asset	42,182	68,938
Liability	27,569	46,333
Not designated as hedging | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional Amount	650,268	606,878
Asset	26,355	34,547
Liability	26,168	34,317
Not designated as hedging | Forward commitments
Derivatives, Fair Value [Line Items]
Notional Amount	1,172,717	1,358,328
Asset	0	0
Liability	1,401	11,633
Not designated as hedging | Interest rate-lock commitments
Derivatives, Fair Value [Line Items]
Notional Amount	787,258	1,191,621
Asset	13,120	34,391
Liability	0	0
Not designated as hedging | Futures contracts
Derivatives, Fair Value [Line Items]
Notional Amount	502,500	375,400
Asset	2,707	0
Liability	0	383
Designated as hedging | Interest rate swaps
Derivatives, Fair Value [Line Items]
Notional Amount	30,000	30,000
Asset	0	0
Liability	$ 1,391	$ 1,909