Income Taxes (Details) - Narrative - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Acquired thrift's tax bad debt reserve	$ 2,500	$ 2,500	$ 2,500
Deferred tax assets, net	100,207	86,693
Unrecognized tax benefit that would affect effective tax rate	1,400	936,000	$ 597,000
NIBancsharesandPeoplesBankAcquisitionsMember [Member]
Income Taxes [Line Items]
Deferred tax assets, net	$ 4,400
Peoples' Bank and Great Lakes Acquisitions [Member]
Income Taxes [Line Items]
Deferred tax assets, net		$ 3,500