Other Comprehensive Income (Loss) - Reclassification of Available-for-Sale Securities to Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification of Available-for-Sale Securities to Held-to-maturity Roll Forward [Roll Forward]
Beginning balance			$ 181,321	$ 172,521
Other comprehensive loss	$ (1,677)	$ (263)	(5,514)	(29)
Ending balance	184,661	179,882	184,661	179,882
Accumulated Net Gain (Loss) on Securities Transferred from Available-for-Sale to Held-to-Maturity
Reclassification of Available-for-Sale Securities to Held-to-maturity Roll Forward [Roll Forward]
Beginning balance	(189)	(137)	(174)	(129)
Amortization of net unrealized losses	(6)	(5)	(25)	(17)
Related deferred taxes (at a Federal Income Tax rate of 21% for September 30, 2018 and 35% for September 30, 2017)	1	2	5	6
Other comprehensive loss	(5)	(3)	(20)	(11)
Ending balance	$ (194)	$ (140)	$ (194)	$ (140)

Reclassification of Available-for-Sale Securities to Held-to-maturity Roll Forward [Roll Forward]

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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Amount before tax of reclassification adjustments of other comprehensive income (loss).

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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