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Securities - Summary of Amortized Cost and Fair Values of Securities Available-for-sale (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	$ 1,183,404	$ 834,254
Available-for-sale Securities, Gross Unrealized Gains	7,593	3,130
Available-for-sale Securities, Gross Unrealized Losses	(4,705)	(19,728)
Available-for-sale Securities, Fair Value	1,186,292	817,656
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	41,403	52,775
Available-for-sale Securities, Gross Unrealized Gains	427	81
Available-for-sale Securities, Gross Unrealized Losses		(189)
Available-for-sale Securities, Fair Value	41,830	52,667
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	165,162	187,427
Available-for-sale Securities, Gross Unrealized Gains	542	367
Available-for-sale Securities, Gross Unrealized Losses	(754)	(1,296)
Available-for-sale Securities, Fair Value	164,950	186,498
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	92,806	60,686
Available-for-sale Securities, Gross Unrealized Gains	2,075	133
Available-for-sale Securities, Gross Unrealized Losses	(49)	(586)
Available-for-sale Securities, Fair Value	94,832	60,233
Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	490,427	284,038
Available-for-sale Securities, Gross Unrealized Gains	2,163	101
Available-for-sale Securities, Gross Unrealized Losses	(2,354)	(11,176)
Available-for-sale Securities, Fair Value	490,236	272,963
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	109,501	84,998
Available-for-sale Securities, Gross Unrealized Gains	593	199
Available-for-sale Securities, Gross Unrealized Losses	(272)	(1,576)
Available-for-sale Securities, Fair Value	109,822	83,621
Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	159,650	93,543
Available-for-sale Securities, Gross Unrealized Gains	1,092	55
Available-for-sale Securities, Gross Unrealized Losses	(1,041)	(3,164)
Available-for-sale Securities, Fair Value	159,701	90,434
Non-Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	31,144	31,458
Available-for-sale Securities, Gross Unrealized Gains	130
Available-for-sale Securities, Gross Unrealized Losses		(1,000)
Available-for-sale Securities, Fair Value	31,274	30,458
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	48,796	34,716
Available-for-sale Securities, Gross Unrealized Gains	571	67
Available-for-sale Securities, Gross Unrealized Losses	(37)	(610)
Available-for-sale Securities, Fair Value	49,330	34,173
Asset-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	44,515
Available-for-sale Securities, Gross Unrealized Losses	(198)
Available-for-sale Securities, Fair Value	$ 44,317
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		4,613
Available-for-sale Securities, Gross Unrealized Gains		2,127
Available-for-sale Securities, Gross Unrealized Losses		(131)
Available-for-sale Securities, Fair Value		$ 6,609

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- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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