Derivatives - Schedule of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jul. 31, 2017	Dec. 31, 2016
Derivatives Fair Value [Line Items]
Notional amount		$ 100,000
Not Designated As Hedging
Derivatives Fair Value [Line Items]
Notional amount	$ 1,881,217		$ 1,384,163
Asset	10,033		19,745
Liability	2,434		586
Not Designated As Hedging | Interest rate contracts
Derivatives Fair Value [Line Items]
Notional amount	139,545		22,243
Asset	1,456		586
Liability	1,456		586
Not Designated As Hedging | Forward commitments
Derivatives Fair Value [Line Items]
Notional amount	851,000		829,000
Asset	154		12,731
Not Designated As Hedging | Interest rate-lock commitments
Derivatives Fair Value [Line Items]
Notional amount	540,672		532,920
Asset	8,423		$ 6,428
Not Designated As Hedging | Futures Contracts
Derivatives Fair Value [Line Items]
Notional amount	350,000
Liability	978
Designated as Hedging
Derivatives Fair Value [Line Items]
Notional amount	130,000
Asset	283
Designated as Hedging | Interest Rate Swaps
Derivatives Fair Value [Line Items]
Notional amount	130,000
Asset	$ 283