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Investment Securities - Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	$ 148,879	$ 157,206
Held to maturity, Fair Value	151,118	153,894
Held-to-maturity, Gross Unrealized Gains	2,598	210
Held-to-maturity, Gross Unrealized Losses	(359)	(3,522)
Total	368,712	465,910
Available-for-sale, at fair value	378,131	462,464
Available-for-sale, Gross Unrealized Gains	9,709	1,748
Available-for-sale, Gross Unrealized Losses	(290)	(5,194)
Total investment securities, Amortized Cost	517,591	623,116
Total investment securities, Fair Value	529,249	616,358
Total investment securities, Gross Unrealized Gains	12,307	1,958
Total investment securities, Gross Unrealized Losses	(649)	(8,716)
MBS pass-through securities issued by FHLMC and FNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	83,493	88,606
Held to maturity, Fair Value	84,121	85,804
Held-to-maturity, Gross Unrealized Gains	967	7
Held-to-maturity, Gross Unrealized Losses	(339)	(2,809)
Total	70,550	95,339
Available-for-sale, at fair value	72,144	94,467
Available-for-sale, Gross Unrealized Gains	1,644	358
Available-for-sale, Gross Unrealized Losses	(50)	(1,230)
SBA-backed securities
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	8,401	8,720
Held to maturity, Fair Value	8,779	8,757
Held-to-maturity, Gross Unrealized Gains	378	37
Held-to-maturity, Gross Unrealized Losses	0	0
Total	38,363	50,722
Available-for-sale, at fair value	39,805	50,781
Available-for-sale, Gross Unrealized Gains	1,498	465
Available-for-sale, Gross Unrealized Losses	(56)	(406)
CMOs issued by FNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	10,972	11,447
Held to maturity, Fair Value	11,250	11,327
Held-to-maturity, Gross Unrealized Gains	278	0
Held-to-maturity, Gross Unrealized Losses	0	(120)
Total	25,832	28,275
Available-for-sale, at fair value	26,175	28,079
Available-for-sale, Gross Unrealized Gains	352	134
Available-for-sale, Gross Unrealized Losses	(9)	(330)
CMOs issued by FHLMC
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	33,095	33,583
Held to maturity, Fair Value	33,880	33,021
Held-to-maturity, Gross Unrealized Gains	805	8
Held-to-maturity, Gross Unrealized Losses	(20)	(570)
Total	142,175	145,979
Available-for-sale, at fair value	146,528	144,836
Available-for-sale, Gross Unrealized Gains	4,410	454
Available-for-sale, Gross Unrealized Losses	(57)	(1,597)
CMOs issued by GNMA
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	3,750	3,739
Held to maturity, Fair Value	3,810	3,769
Held-to-maturity, Gross Unrealized Gains	60	30
Held-to-maturity, Gross Unrealized Losses	0	0
Total	13,275	11,294
Available-for-sale, at fair value	13,268	11,021
Available-for-sale, Gross Unrealized Gains	33	1
Available-for-sale, Gross Unrealized Losses	(40)	(274)
Debentures of government- sponsored agencies
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Total	28,035	52,956
Available-for-sale, at fair value	28,784	53,018
Available-for-sale, Gross Unrealized Gains	749	185
Available-for-sale, Gross Unrealized Losses	0	(123)
Privately issued CMOs
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Total	159	295
Available-for-sale, at fair value	159	297
Available-for-sale, Gross Unrealized Gains	1	2
Available-for-sale, Gross Unrealized Losses	(1)	0
Obligations of state and political subdivisions
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	9,168	11,111
Held to maturity, Fair Value	9,278	11,216
Held-to-maturity, Gross Unrealized Gains	110	128
Held-to-maturity, Gross Unrealized Losses	0	(23)
Total	48,323	79,046
Available-for-sale, at fair value	49,259	77,960
Available-for-sale, Gross Unrealized Gains	1,012	134
Available-for-sale, Gross Unrealized Losses	(76)	(1,220)
Corporate bonds
Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items]
Total	2,000	2,004
Available-for-sale, at fair value	2,009	2,005
Available-for-sale, Gross Unrealized Gains	10	15
Available-for-sale, Gross Unrealized Losses	$ (1)	$ (14)

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