Fair Value of Financial Instruments - Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets:
Securities available for sale, at fair value	$ 272,205	$ 346,502	[1]
Level 1
Assets:
Securities available for sale, at fair value	0	0
Level 2
Assets:
Securities available for sale, at fair value	272,205	346,502
Level 3
Assets:
Securities available for sale, at fair value	0	0
Federal agencies and GSEs
Assets:
Securities available for sale, at fair value	86,923	104,054
Mortgage-backed and CMOs
Assets:
Securities available for sale, at fair value	79,896	79,493
State and municipal
Assets:
Securities available for sale, at fair value	94,783	147,515
Corporate
Assets:
Securities available for sale, at fair value	8,344	13,492
Equity securities
Assets:
Securities available for sale, at fair value	2,259	1,948
Fair Value, Measurements, Recurring
Assets:
Securities available for sale, at fair value	272,205	346,502
Fair Value, Measurements, Recurring | Level 1
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Level 2
Assets:
Securities available for sale, at fair value	272,205	346,052
Fair Value, Measurements, Recurring | Level 3
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Federal agencies and GSEs
Assets:
Securities available for sale, at fair value	86,923	104,054
Fair Value, Measurements, Recurring | Federal agencies and GSEs | Level 1
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Federal agencies and GSEs | Level 2
Assets:
Securities available for sale, at fair value	86,923	104,054
Fair Value, Measurements, Recurring | Federal agencies and GSEs | Level 3
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Mortgage-backed and CMOs
Assets:
Securities available for sale, at fair value	79,896	79,493
Fair Value, Measurements, Recurring | Mortgage-backed and CMOs | Level 1
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Mortgage-backed and CMOs | Level 2
Assets:
Securities available for sale, at fair value	79,896	79,493
Fair Value, Measurements, Recurring | Mortgage-backed and CMOs | Level 3
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | State and municipal
Assets:
Securities available for sale, at fair value	94,783	147,515
Fair Value, Measurements, Recurring | State and municipal | Level 1
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | State and municipal | Level 2
Assets:
Securities available for sale, at fair value	94,783	147,515
Fair Value, Measurements, Recurring | State and municipal | Level 3
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Corporate
Assets:
Securities available for sale, at fair value	8,344	13,492
Fair Value, Measurements, Recurring | Corporate | Level 1
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Corporate | Level 2
Assets:
Securities available for sale, at fair value	8,344	13,492
Fair Value, Measurements, Recurring | Corporate | Level 3
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Equity securities
Assets:
Securities available for sale, at fair value	2,259	1,948
Fair Value, Measurements, Recurring | Equity securities | Level 1
Assets:
Securities available for sale, at fair value	0	0
Fair Value, Measurements, Recurring | Equity securities | Level 2
Assets:
Securities available for sale, at fair value	2,259	1,498
Fair Value, Measurements, Recurring | Equity securities | Level 3
Assets:
Securities available for sale, at fair value	$ 0	$ 0

[1] Derived from audited consolidated financial statements.