Accumulated Other Comprehensive (Loss) Income - Summary of reclassifications out of accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	12 Months Ended	24 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2016
Consolidated Statements of Comprehensive Income
Realized gain on securities sales, AFS	$ 0	$ 0	$ (6)	$ (6)
Income tax expense	0		(2)
Total reclassifications, net of tax	$ 0	$ (222)	$ 4

Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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