Effect of Master Netting Arrangements on Presentation of Derivative Assets and Liabilities in Consolidated Statements of Financial Condition (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Derivative Financial Instruments, Liabilities
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Liabilities	$ 5,724	$ 8,012
Gross Amounts Offset in the Statement of Condition	4,687	7,624
Net Amounts of Liabilities Presented in the Statement of Condition	1,037	388
Financial Instruments	0	0
Cash Collateral Received	0	0
Net Amount	1,037	388
Derivative Financial Instruments, Assets
Derivatives, Fair Value [Line Items]
Gross Amounts Of Recognized Assets	11,573	6,680
Gross Amounts offset in the statement of Condition	4,324	4,848
Net Amounts of Assets Presented in the Statement of Condition	7,249	1,832
Financial Instruments	0	0
Cash Collateral Received	0	0
Net Amount	$ 7,249	$ 1,832