Core Deposit Intangibles - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2016	Jun. 30, 2017	Dec. 31, 2016	May 19, 2017	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Measurement period adjustment			$ 2,142
Arlington Bank
Finite-Lived Intangible Assets [Line Items]
Core deposit intangible				$ 4,526
Ameriana
Finite-Lived Intangible Assets [Line Items]
Core deposit intangible					$ 5,342
Measurement period adjustment	$ 2,142