Mergers and Acquisitions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Apr. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Reported assets of acquiree		$ 692,135	$ 600,595
Goodwill		10,288	3,664
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2017		196
2018		26
2019		21
2020		16
Thereafter		66
Acquisition costs		401	134
United American Savings Bank
Business Acquisition [Line Items]
Payments to acquire businesses, gross	$ 13,200
Acquisition share price (in dollars per share)	$ 42.67
Goodwill	$ 6,624	6,600
Core deposit intangible	232
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2016		31
2017		40
2018		32
2019		26
2020		20
Thereafter		83
Loans receivable	66,145
Reduction for credit-related adjustment	927
Adjustment for other factors	$ 982
Acquisition costs		401
United American Savings Bank | Legal Fees
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Acquisition costs		194
United American Savings Bank | System Conversion Costs
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Acquisition costs		132
United American Savings Bank | Other Professional Fees
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Acquisition costs		$ 75
United American Savings Bank | Core Deposits
Business Acquisition [Line Items]
Weighted average useful life	10 years
United American Savings Bank
Business Acquisition [Line Items]
Reported assets of acquiree			$ 89,300