Securities - Summary of securities in unrealized loss position (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	$ 10,459	$ 28,712
Gross Unrealized Losses, Less than 12 Months	(85)	(172)
Fair Value, 12 Months or Longer	41,415	101,272
Gross Unrealized Losses, 12 Months or Longer	(434)	(3,474)
Fair Value, Total	51,874	129,984
Gross Unrealized Losses, Total	(519)	(3,646)
Mortgage-backed securities – agency
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months		9,528
Gross Unrealized Losses, Less than 12 Months		(99)
Fair Value, 12 Months or Longer	9,926	15,497
Gross Unrealized Losses, 12 Months or Longer	(93)	(625)
Fair Value, Total	9,926	25,025
Gross Unrealized Losses, Total	(93)	(724)
CMO's - agency
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 Months	10,459	19,184
Gross Unrealized Losses, Less than 12 Months	(85)	(73)
Fair Value, 12 Months or Longer	31,489	85,775
Gross Unrealized Losses, 12 Months or Longer	(341)	(2,849)
Fair Value, Total	41,948	104,959
Gross Unrealized Losses, Total	$ (426)	$ (2,922)