Derivative Financial Instruments - Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	$ 715	$ 608
Total Liability Derivatives	2,850	3,160
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	429	6
Total Liability Derivatives	2,819	3,138
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Contracts One [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liability Derivatives	429	6
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Contracts Two [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liability Derivatives	2,390	3,132
Derivatives Designated as Hedging Instruments [Member] | Interest Rate Contracts Two [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	429	6
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	286	602
Total Liability Derivatives	31	22
Derivatives Not Designated as Hedging Instruments [Member] | Mortgage Loan Contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Liability Derivatives	31	22
Derivatives Not Designated as Hedging Instruments [Member] | Mortgage Loan Contracts [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Total Asset Derivatives	$ 286	$ 602