Acquisitions (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended								12 Months Ended
	Jan. 06, 2016	Jul. 17, 2015	Mar. 06, 2015	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition
Acquired intangibles												$ 10,318	$ 4,999
Acquired goodwill												34,069	28,042
Non-interest expense related to acquisitions				$ 10,700								10,700
Net loss on asset disposals and other transactions				(498)	$ (51)	$ (136)	$ (1,103)	$ (146)	$ (109)	$ (187)	$ 11	(1,788)	(431)	$ (155)
Goodwill				132,631				$ 98,562				132,631	98,562	$ 70,520
NB&T Financial Group, Inc. [Member]
Business Acquisition
Business Acquisition, Pro Forma Revenue												149,965	141,221
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments, Other Assets				(600)
Total purchase price			$ 102,700									102,709
Net loss on asset disposals and other transactions												(600)
Shares, Outstanding			3,442,329
Cash purchase price per share			$ 23.70
Number of common shares of Peoples issued for each common share of acquired company			0.9319
Goodwill, Purchase Accounting Adjustments				600
Goodwill				33,637								33,637
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual													26,200
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual													7,800
Business Acquisition, Pro Forma Net Income (Loss)												12,259	$ 23,512
NB&T Financial Group, Inc. [Member] | Cash Portion of Purchase Price
Business Acquisition
Cash purchase price per share			$ 7.75
Lebanon, Ohio Insurance Agency [Member]
Business Acquisition
Total purchase price		$ 900
Acquired intangibles		500
Acquired goodwill		$ 400
Salaries and Employee Benefit Costs [Member]
Business Acquisition
Non-interest expense related to acquisitions				4,400								4,400
Professional Service Fees [Member]
Business Acquisition
Non-interest expense related to acquisitions				1,700								1,700
Other Non-Interest Expenses [Member]
Business Acquisition
Non-interest expense related to acquisitions				4,300								4,300
Data processing and software expense [Member]
Business Acquisition
Non-interest expense related to acquisitions				$ 300								$ 300
Subsequent Event [Member] | Marietta, Ohio financial advisory book of business [Member]
Business Acquisition
Total purchase price	$ 500