Derivatives and Hedging Activities - Carrying amount and hedge accounting basis adjustment (Details) - Fair value hedge - Interest rate swaps - Deposits - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Carrying amount of Assets (Liabilities)	$ (35,880)	$ (35,776)
Hedge Accounting Basis Adjustment	$ 645	$ 1,838