Acquisitions (Goodwill) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 98,562
Goodwill, ending balance	132,252
Goodwill
Goodwill [Roll Forward]
Goodwill, beginning balance	98,562
Goodwill, ending balance	132,252
Gross Core Deposit
Intangible Assets [Roll Forward]
Gross Intangible Assets	13,546
Gross Intangible Assets	22,169
Gross Customer Relationship
Intangible Assets [Roll Forward]
Gross Intangible Assets	8,859
Gross Intangible Assets	10,121
NB&T Financial Group, Inc.
Goodwill [Roll Forward]
Goodwill, ending balance	33,700
NB&T Financial Group, Inc. | Goodwill
Goodwill [Roll Forward]
Acquired goodwill	33,690
NB&T Financial Group, Inc. | Gross Core Deposit
Intangible Assets [Roll Forward]
Acquired intangible assets	8,623
NB&T Financial Group, Inc. | Gross Customer Relationship
Intangible Assets [Roll Forward]
Acquired intangible assets	$ 1,262