Other Comprehensive Income (Loss) - Reclassification of Available-for-Sale Securities to Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification of Available-for-Sale Securities to Held-to-maturity Roll Forward [Roll Forward]
Beginning balance			$ 181,321	$ 172,521
Other comprehensive income (loss)	$ (904)	$ 174	(3,837)	234
Ending balance	183,304	177,537	183,304	177,537
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	(182)	(133)	(174)	(129)
Amortization of net unrealized losses	(9)	(6)	(19)	(12)
Related deferred taxes (at a Federal Income Tax rate of 21% for June 30, 2018 and 35% for June 30, 2017)	2	2	4	4
Other comprehensive income (loss)	(7)	(4)	(15)	(8)
Ending balance	$ (189)	$ (137)	$ (189)	$ (137)

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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