Derivative Financial Instruments - Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	$ 4,485	$ 177
Total Liability Derivatives	6,959	1,802
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	4,093	42
Total Liability Derivatives	6,959	1,802
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Contracts One [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liability Derivatives	4,093	42
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Contracts Two [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liability Derivatives	2,866	1,760
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Contracts Two [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	4,093	42
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	392	135
Total Liability Derivatives	0	0
Derivatives Not Designated as Hedging Instruments [Member] | Mortgage Loan Contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liability Derivatives	0	0
Derivatives Not Designated as Hedging Instruments [Member] | Mortgage Loan Contracts [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	$ 392	$ 135