Debt Securities Held to Maturity Expected Maturities of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Amortized Cost
Amortized cost	$ 289,089	$ 262,143
Fair Value
Fair value	296,325	254,841
U.S. government and agency obligations
Amortized Cost
More than five years to ten years	5,000
More than ten years	20,000
Amortized cost	25,000	23,404
Fair Value
More than five years to ten years	5,002
More than ten years	19,926
Fair value	24,928	23,241
Mortgage-backed securities and collateralized mortgage obligations
Amortized Cost
Amortized cost	264,089	238,739
Fair Value
Fair value	$ 271,397	$ 231,600

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

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