Goodwill and other intangible assets (Details) $ in Thousands		6 Months Ended
	Mar. 04, 2016 USD ($) location	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Goodwill [Line Items]
Goodwill		$ 82,594		$ 78,610
Core Deposits
Goodwill [Line Items]
Useful life		10 years
Bank Of America, Branch Locations
Goodwill [Line Items]
Number of Businesses Acquired | location	15
Goodwill	$ 3,984		$ 4,000
Bank Of America, Branch Locations | Core Deposits
Goodwill [Line Items]
Useful life	9 years 12 months
Home Federal Bank
Goodwill [Line Items]
Goodwill					$ 78,600