Merger accounting - Calculation of Consideration Effectively Transferred (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended	0 Months Ended
	Dec. 31, 2013	Nov. 30, 2013 Penseco Financial Services Corp [Member]	Nov. 30, 2013 Reverse Merger [Member]	Nov. 30, 2013 Reverse Merger [Member] Peoples Financial Services Corp [Member]	Nov. 30, 2013 Reverse Merger [Member] Penseco Financial Services Corp [Member]
Business Acquisition [Line Items]
Shares outstanding			3,275,217	3,087,406	3,275,217
Exchange ratio	1.3636	1.3636	1.3636
Share to be issued to acquiree share holders			4,465,538
Common shares to be outstanding			7,552,944
Ownership percentage				40.88%	59.12%
Theoretical Penseco share to be issued as consideration
Shares outstanding			3,275,217	3,087,406	3,275,217
Ownership % to be owned by current acquiree's shareholders			59.12%
Theoretical shares after consideration paid			5,539,653
Ownership by legacy acquirer's shareholders			40.88%
Theoretical Penseco shares issued as consideration			2,264,436
Fair value of acquiree's shares			$ 47.04
Fair value of theoretical shares offered			$ 106,519
Cash paid for fractional shares			17
Total purchase price for accounting purposes			$ 106,536