Borrowings - Maturities of FHLB advances (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Maturities of FHLB advances
Total	$ 181,439	$ 195,453
FHLB advances
Maturities of FHLB advances
Due within one year	145,589
Due in one year to two years	15,077
Due in two years to three years	59
Due in three years to four years	342
Due in four years to five years	61
Thereafter	1,571
Total	$ 162,699	$ 151,721