Securities Held-to-Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized cost	$ 262,143	$ 239,618
Gross unrealized gains	73	0
Gross unrealized (losses)	(7,375)	(3,493)
Securities held to maturity	254,841	236,125
U.S. government and agency obligations
Schedule of Held-to-maturity Securities [Line Items]
Amortized cost	23,404	8,402
Gross unrealized gains	45	0
Gross unrealized (losses)	(208)	(58)
Securities held to maturity	23,241	8,344
Mortgage-backed securities and collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Amortized cost	238,739	231,216
Gross unrealized gains	28	0
Gross unrealized (losses)	(7,167)	(3,435)
Securities held to maturity	$ 231,600	$ 227,781

Amount of investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 45
-Paragraph 1
-Subparagraph (b)
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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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