Goodwill and Intangible Assets - Additional Information (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($) acquisition	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) acquisition	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Number of acquisitions resulting in goodwill | acquisition	4		4
Business Acquisition [Line Items]
Goodwill impairment loss			$ 0		$ 0
Number of acquisitions resulting in core deposit intangible assets | acquisition	2		2
Intangible asset amortization	$ 59,000	$ 56,000	$ 119,000	$ 105,000
United American Savings Bank
Business Acquisition [Line Items]
Goodwill					$ 6,600,000