Expected Maturities of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized cost
Amortized cost	$ 262,143	$ 239,618
Fair value
Fair value	254,841	236,125
U.S. government and agency obligations
Amortized cost
More than one year to five years	5,000
More than five years to ten years	8,404
More than ten years	10,000
Amortized cost	23,404	8,402
Fair value
More than one year to five years	5,000
More than five years to ten years	8,196
More than ten years	10,045
Fair value	23,241	8,344
Mortgage-backed securities and collateralized mortgage obligations
Amortized cost
Amortized cost	238,739	231,216
Fair value
Fair value	$ 231,600	$ 227,781

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

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