Postretirement Benefit Plans (Details) (Narrative) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Cash Surrender Value of Bank Owned Life Insurance	$ 3,513,000	$ 3,408,000
Defined Benefit Postretirement Health Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Minimum Service Period Requirement	20 years
Defined Benefit Plan, Maximum Coverage Period	5 years
Defined Benefit Plan, Amended Eligibility Criteria	This Plan was amended in 2008 to encompass only those employees that had achieved ten years of full-time continuous service to Mid Penn as of January 1, 2008. Employees hired after that date and those that had not achieved the service requirements are not eligible for the Plan.
Defined Benefit Postretirement Life Insurance [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Minimum Service Period Requirement	20 years
Defined Benefit Plan, Benefit Description, Prior To Age 65	be three times the participant's annual salary at retirement or $50,000, whichever is less
Defined Benefit Plan, Benefit Description, After Age 65	life insurance coverage amount will decrease by 10% per year, subject to a minimum amount of $2,000
Defined Benefit Postretirement Health And Life Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost, before Tax	(2,000)	(3,000)
Defined Benefit Plan, Accumulated Benefit Obligation	894,000	904,000
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	1,053
Director's Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized Prior Service Cost Generated By Adoption of the Plan	274,000
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost, before Tax	129,000	151,000
Defined Benefit Plan, Accumulated Benefit Obligation	1,139,000	1,069,000
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	$ 21,525