Derivative Financial Instruments - Summary of Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Total derivative assets	$ 70,346	$ 29,005
Total derivative liabilities	15,484	12,550
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total derivative assets	8,937	12,741
Total derivative liabilities	1,115	1,603
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Total derivative assets	8,937	12,741
Total derivative liabilities	1,115	1,603
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total derivative assets	61,409	16,264
Total derivative liabilities	14,369	10,947
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Total derivative assets	57,695	15,278
Total derivative liabilities	14,214	10,562
Not Designated as Hedging Instrument [Member] | Mortgage Contracts [Member]
Derivative [Line Items]
Total derivative assets	3,510	874
Total derivative liabilities		316
Not Designated as Hedging Instrument [Member] | Foreign Currency Contracts [Member]
Derivative [Line Items]
Total derivative assets	204	112
Total derivative liabilities	$ 155	$ 69