Derivative Financial Instruments - Summary of Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Total derivative assets	$ 39,952	$ 29,005
Total derivative liabilities	11,546	12,550
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total derivative assets	18,231	12,741
Total derivative liabilities	2,351	1,603
Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Total derivative assets	18,231	12,741
Total derivative liabilities	2,351	1,603
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total derivative assets	21,721	16,264
Total derivative liabilities	9,195	10,947
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Total derivative assets	19,749	15,278
Total derivative liabilities	8,849	10,562
Not Designated as Hedging Instrument [Member] | Mortgage Contracts [Member]
Derivative [Line Items]
Total derivative assets	1,872	874
Total derivative liabilities	292	316
Not Designated as Hedging Instrument [Member] | Foreign Currency Contracts [Member]
Derivative [Line Items]
Total derivative assets	100	112
Total derivative liabilities	$ 54	$ 69