Offsetting Assets and Liabilities - Gross and Net Amounts of Derivative Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Interest rate commitments
Derivative Instruments, Gain (Loss) [Line Items]
Gross Amounts of Recognized Assets	$ 189	$ 154
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amount of Assets Presented in the Consolidated Balance Sheets	189	154
Gross Amounts of Recognized Liabilities	6	14
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amount of Assets Presented in the Consolidated Balance Sheets	6	14
Interest rate swap contacts
Derivative Instruments, Gain (Loss) [Line Items]
Gross Amounts of Recognized Assets	2,081
Gross Amounts Offset in the Consolidated Balance Sheets	0
Net Amount of Assets Presented in the Consolidated Balance Sheets	2,081
Gross Amounts of Recognized Liabilities	2,081
Gross Amounts Offset in the Consolidated Balance Sheets	0
Net Amount of Assets Presented in the Consolidated Balance Sheets	2,081
Forward sale contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gross Amounts of Recognized Assets		2
Gross Amounts Offset in the Consolidated Balance Sheets		0
Net Amount of Assets Presented in the Consolidated Balance Sheets		2
Gross Amounts of Recognized Liabilities	90	174
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amount of Assets Presented in the Consolidated Balance Sheets	90	174
Repurchase agreements
Derivative Instruments, Gain (Loss) [Line Items]
Gross Amounts of Recognized Liabilities	2,438	3,569
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amount of Assets Presented in the Consolidated Balance Sheets	$ 2,438	$ 3,569