Investment Securities - Summary of Carrying Amounts of Securities and Their Approximate Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost	$ 141,109	$ 172,290
Available for sale securities, Gross Unrealized Gains	231	118
Available for sale securities, Gross Unrealized Losses	(1,010)	(4,245)
Available for sale securities, Fair Value	140,330	168,163
Held to maturity securities, Amortized Cost	258,172	282,869
Held to maturity securities, Gross Unrealized Gains	6,119	1,431
Held to maturity securities, Gross Unrealized Losses	(177)	(2,990)
Held to maturity securities, Fair Value	264,114	281,310
Total, Amortized Cost	399,281	455,159
Total, Gross Unrealized Gains	6,350	1,549
Total, Gross Unrealized Losses	(1,187)	(7,235)
Total, Fair Value	404,444	449,473
U.S. GSE Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost	38,000	75,004
Available for sale securities, Gross Unrealized Losses	(152)	(965)
Available for sale securities, Fair Value	37,848	74,039
Held to maturity securities, Amortized Cost	5,000	32,571
Held to maturity securities, Gross Unrealized Losses		(238)
Held to maturity securities, Fair Value	5,000	32,333
Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost		5,015
Available for sale securities, Gross Unrealized Losses		(159)
Available for sale securities, Fair Value		4,856
Held to maturity securities, Amortized Cost	6,980	6,972
Held to maturity securities, Gross Unrealized Gains	116
Held to maturity securities, Gross Unrealized Losses		(107)
Held to maturity securities, Fair Value	7,096	6,865
Mortgage Backed Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost	103,109	92,271
Available for sale securities, Gross Unrealized Gains	231	118
Available for sale securities, Gross Unrealized Losses	(858)	(3,121)
Available for sale securities, Fair Value	102,482	89,268
Held to maturity securities, Amortized Cost	161,759	168,118
Held to maturity securities, Gross Unrealized Gains	2,751	134
Held to maturity securities, Gross Unrealized Losses	(111)	(2,290)
Held to maturity securities, Fair Value	164,399	165,962
Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Held to maturity securities, Amortized Cost	84,433	75,208
Held to maturity securities, Gross Unrealized Gains	3,252	1,297
Held to maturity securities, Gross Unrealized Losses	(66)	(355)
Held to maturity securities, Fair Value	$ 87,619	$ 76,150

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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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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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