Securities - Summary of Amortized Cost and Fair Value of Securities Available for Sale and Held to Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Securities available for sale [Abstract]
Amortized Cost	$ 148,108	$ 186,254
Gross unrealized gains	204	82
Gross unrealized (losses)	(1,712)	(3,981)
Estimated fair value	146,600	182,355
Securities held to maturity [Abstract]
Amortized Cost	45,635	46,864
Gross unrealized gains	3,345	2,874
Gross unrealized (losses)		(7)
Estimated fair value	48,980	49,731
U. S. government agency securities
Securities available for sale [Abstract]
Amortized Cost	11,434	9,517
Gross unrealized gains	18
Gross unrealized (losses)	(153)	(143)
Estimated fair value	11,299	9,374
State and municipal securities
Securities available for sale [Abstract]
Amortized Cost	19,031	28,480
Gross unrealized gains	172	65
Gross unrealized (losses)	(136)	(632)
Estimated fair value	19,067	27,913
Securities held to maturity [Abstract]
Amortized Cost	36,469	36,842
Gross unrealized gains	3,138	2,784
Estimated fair value	39,607	39,626
Mortgage-backed securities
Securities available for sale [Abstract]
Amortized Cost	96,975	126,637
Gross unrealized gains	14	17
Gross unrealized (losses)	(1,166)	(2,059)
Estimated fair value	95,823	124,595
Securities held to maturity [Abstract]
Amortized Cost	3,837	4,687
Gross unrealized gains	77	79
Estimated fair value	3,914	4,766
Asset-backed securities
Securities available for sale [Abstract]
Amortized Cost	20,668	21,620
Gross unrealized (losses)	(257)	(1,147)
Estimated fair value	20,411	20,473
Other debt securities
Securities held to maturity [Abstract]
Amortized Cost	5,329	5,335
Gross unrealized gains	130	11
Gross unrealized (losses)		(7)
Estimated fair value	$ 5,459	$ 5,339

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity.

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Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity.

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

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Fair value of investments in debt securities classified as held-to-maturity.

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