EARNINGS PER SHARE - Computation of basic and diluted EPS (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net income	$ 1,453us-gaap_NetIncomeLoss	$ 1,066us-gaap_NetIncomeLoss
Preferred stock dividends		91
Allocated to participating securities	14rivr_AllocatedToParticipatingSecurities
Net income allocated to common shareholders	$ 1,439	$ 975
Weighted average common shares outstanding, gross	2,513,696	1,533,333
Less: Average participating securities	24,000rivr_AverageParticipatingSecurities
Weighted average common shares outstanding, net	2,489,696	1,533,333
Effect of diluted based awards	2,834	4,636
Weighted average shares and common stock equivalents	2,492,530	1,537,969
Income per common share:
Basic (in dollars per share)	$ 0.58us-gaap_EarningsPerShareBasic	$ 0.64us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ 0.58us-gaap_EarningsPerShareDiluted	$ 0.63us-gaap_EarningsPerShareDiluted
Options excluded from the calculation due to their anti-dilutive effect on earnings per share	30,000

Represents allocated to participating securities.

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- Definition

Represents average participating securities.

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No definition available.

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- Definition

Represents net income loss available to common stockholders basic net of preferred stock and participating securities.

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No definition available.

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- Definition

Represents weighted average common shares outstanding net of average participating securities.

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No definition available.

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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- Definition

The amount of preferred stock dividends that is an adjustment to net income apportioned to common stockholders.

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No definition available.

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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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- Definition

This element represents the weighted average total number of shares issued throughout the period including the first (beginning balance outstanding) and last (ending balance outstanding) day of the period before considering any reductions (for instance, shares held in treasury) to arrive at the weighted average number of shares outstanding. Weighted average relates to the portion of time within a reporting period that common shares have been issued and outstanding to the total time in that period. Such concept is used in determining the weighted average number of shares outstanding for purposes of calculating earnings per share (basic).

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