Borrowings - Summary of Balances for Securities Sold Under Agreements to Repurchase (Details) - Mortgage Backed Securities - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Assets Sold under Agreements to Repurchase [Line Items]
Balance at year end	$ 15,081	$ 14,293
Average daily balance during the year	$ 16,128	$ 16,326
Average interest rate during the year	0.28%	0.17%
Maximum month-end balance during the year	$ 19,651	$ 19,432
Weighted average interest rate at year-end	0.74%	0.16%