Acquisitions - Pro Forma Result of Comparable Prior Reporting Period (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition, Pro Forma Information [Abstract]
Net Interest Income	$ 28,856	$ 26,628	$ 84,471	$ 80,515
Provision for Loan Losses	725	455	1,438	1,219
Net Interest Income after Provision for Loan Losses	28,131	26,173	83,033	79,296
Non-interest Income	8,077	10,534	24,175	32,547
Non-Interest Expense	26,523	32,400	73,003	86,781
Income before Income Taxes	9,685	4,307	34,205	25,062
Income Tax Expense	2,394	1,997	9,260	8,328
Net Income	7,291	2,310	24,945	16,734
Net Income Available to Common Shareholders	$ 7,291	$ 2,310	$ 24,945	$ 16,692
Basic Earnings Per Share	$ 0.32	$ 0.11	$ 1.12	$ 0.87
Diluted Earnings Per Share	$ 0.32	$ 0.11	$ 1.11	$ 0.86
Weighted average common shares outstanding	22,580,160	21,538,752	22,326,454	19,252,295
Weighted average shares outstanding	22,715,273	21,651,953	22,455,798	19,346,376