Securities - Schedule of Contractual Maturities of Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]
After 1 year through 5 years, Held to Maturity, Amortized Cost	$ 15,630
After 5 years through 10 years, Held to Maturity, Amortized Cost	15,048
Single Maturity Date, Held to Maturity, Amortized Cost	30,678
Mortgage- and asset-backed securities and collateralized mortgage obligations - Amortized Basis	273,358
Amortized Cost	304,036	$ 303,716
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Fair Value [Abstract]
After 1 year through 5 years, Held to Maturity, Fair Value	15,225
After 5 years through 10 years, Held to Maturity, Fair Value	14,266
Single Maturity Date, Held to Maturity, Fair Value	29,491
Mortgage- and asset-backed securities and collateralized mortgage obligations - Fair Value	265,981
Held-to-maturity securities, total debt securities	$ 295,472	$ 299,114

Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair value of held-to-maturity debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, maturing in the fifth through tenth fiscal year following the latest fiscal year.

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Fair value of held-to-maturity debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of investment in held-to-maturity debt securities with a single maturity date, after other than temporary impairment (OTTI) accretion.

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Amount of held-to-maturity debt securities at fair value that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the fair value over several maturity groupings.

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