Borrowings - Contractual maturity of the securities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Securities sold under agreement to repurchase
Amounts outstanding at year-end	$ 2,851	$ 5,741
Gross amount of recognized liabilities for repurchase agreements	2,851	5,741
Mortgage Backed Securities, Other [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	2,851	4,199
Collateralized mortgage obligations [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end		1,542
Maturity Overnight [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	2,851	5,741
Maturity Overnight [Member] | Mortgage Backed Securities, Other [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	2,851	4,199
Maturity Overnight [Member] | Collateralized mortgage obligations [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end		1,542
Up to 30 [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	0	0
Up to 30 [Member] | Mortgage Backed Securities, Other [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	0	0
Up to 30 [Member] | Collateralized mortgage obligations [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end		0
Maturity 30 to 90 Days [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	0	0
Maturity 30 to 90 Days [Member] | Mortgage Backed Securities, Other [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	0	0
Maturity 30 to 90 Days [Member] | Collateralized mortgage obligations [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end		0
Maturity Greater than 90 Days [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	0	0
Maturity Greater than 90 Days [Member] | Mortgage Backed Securities, Other [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end	$ 0	0
Maturity Greater than 90 Days [Member] | Collateralized mortgage obligations [Member]
Securities sold under agreement to repurchase
Amounts outstanding at year-end		$ 0