SHARE-BASED COMPENSATION PLANS - Information Pertaining to Options Outstanding and Exercisable (Details) - Orrstown 2011 Incentive Stock Plan - Employee Stock Option	6 Months Ended
Jun. 30, 2019 $ / shares shares
$21.14 - $24.99
Range of Exercise Prices
Range of Exercise Prices, Minimum (in usd per share)	$ 21.14
Range of Exercise Prices, Maximum (in usd per share)	$ 24.99
Number Outstanding (in shares) \| shares	27,767
Weighted Average Remaining Contractual Life (Years)	1 year 21 days
Weighted Average Exercise Price (in usd per share)	$ 21.14
$25.00 - $34.99
Range of Exercise Prices
Range of Exercise Prices, Minimum (in usd per share)	25.00
Range of Exercise Prices, Maximum (in usd per share)	$ 34.99
Number Outstanding (in shares) \| shares	2,792
Weighted Average Remaining Contractual Life (Years)	9 months 3 days
Weighted Average Exercise Price (in usd per share)	$ 25.76
$35.00 - $37.59
Range of Exercise Prices
Range of Exercise Prices, Minimum (in usd per share)	35.00
Range of Exercise Prices, Maximum (in usd per share)	$ 37.59
Number Outstanding (in shares) \| shares	5,090
Weighted Average Remaining Contractual Life (Years)	29 days
Weighted Average Exercise Price (in usd per share)	$ 36.95
$21.14 - $37.59
Range of Exercise Prices
Range of Exercise Prices, Minimum (in usd per share)	21.14
Range of Exercise Prices, Maximum (in usd per share)	$ 37.59
Number Outstanding (in shares) \| shares	35,649
Weighted Average Remaining Contractual Life (Years)	10 months 24 days
Weighted Average Exercise Price (in usd per share)	$ 23.76

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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-Publisher FASB
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-Topic 718
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The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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-Publisher FASB
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- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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