Quarterly Financial Data - Schedule of Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 38,056	$ 36,705	$ 26,112	$ 25,734	$ 25,747	$ 25,704	$ 25,622	$ 24,910	$ 126,607	$ 101,983	$ 76,192
Interest expense	3,884	3,836	2,451	2,211	2,278	2,220	2,133	1,434	12,382	8,065	3,996
Net interest income	34,172	32,869	23,661	23,523	23,469	23,484	23,489	23,476	114,225	93,918	72,196
Provision for loan and lease losses	2,250	1,415	830	326	917	670	1,141	1,074	4,821	3,802	3,607
Net interest income after provision for loan and lease losses	31,922	31,454	22,831	23,197	22,552	22,814	22,348	22,402	109,404	90,116	68,589
Noninterest income	13,994	14,137	14,001	13,831	13,188	12,736	13,242	13,259	55,963	52,425	48,344
Total noninterest expense	38,430	47,066	29,546	26,939	26,029	25,243	26,832	27,411	141,981	105,515	87,254
Income before income taxes	7,486	(1,475)	7,286	10,089	9,711	10,307	8,758	8,250	23,386	37,026	29,679
Income taxes	568	(1,533)	2,046	2,800	2,553	2,779	2,292	2,134	3,881	9,758	7,448
Net income	$ 6,918	$ 58	$ 5,240	$ 7,289	$ 7,158	$ 7,528	$ 6,466	$ 6,116	$ 19,505	$ 27,268	$ 22,231
Weighed average shares outstanding - basic earnings per share	26,300	26,273	19,434	19,402	19,356	19,337	19,501	19,776	22,871	19,491	16,056
Weighed average shares outstanding - diluted earnings per share	26,436	26,340	19,469	19,433	19,395	19,368	19,530	19,800	22,931	19,522	16,079
Net income per share:
Basic (in dollars per share)	$ 0.27	$ 0.00	$ 0.27	$ 0.37	$ 0.37	$ 0.39	$ 0.33	$ 0.31	$ 0.85	$ 1.39	$ 1.37
Diluted (in dollars per share)	0.27	0.00	0.27	0.37	0.37	0.39	0.33	0.31	0.84	1.39	1.37
Dividends per share	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.80	$ 0.80	$ 0.80