Derivative Instruments and Hedge Activities - Summary of Company's Interest Rate Derivative and Offsetting Positions (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative assets fair value	$ 3,913	$ 4,317
Net amount presented in the Consolidated Statements of Financial Condition	3,913
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(677)
Collateral posted	(2,949)
Net credit exposure	287
Derivative liabilities fair value	1,190	$ 559
Net amount presented in the Consolidated Statements of Financial Condition	1,190
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(677)
Collateral posted	(502)
Net credit exposure	$ 11

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