Investment Securities - Portfolio of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 434,749	$ 443,928
Unrealized Gains	3,498	1,795
Unrealized Losses	3,568	7,969
Fair Value	434,679	437,754
U.S. Agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,868	3,016
Unrealized Gains	109	56
Unrealized Losses	0	0
Fair Value	2,977	3,072
State, county, and municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	28,492	44,639
Unrealized Gains	352	214
Unrealized Losses	187	765
Fair Value	28,657	44,088
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	385,321	370,706
Unrealized Gains	2,757	1,092
Unrealized Losses	2,820	5,921
Fair Value	385,258	365,877
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,068	25,567
Unrealized Gains	280	433
Unrealized Losses	561	1,283
Fair Value	$ 17,787	$ 24,717

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).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount, before tax, of unrealized loss 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).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562

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