Consolidated Quarterly Results of Operations - Summary of Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]
Total interest income	$ 34,437	$ 31,973	$ 29,034	$ 28,580	$ 28,394	$ 26,927	$ 25,781	$ 25,355	$ 124,024	$ 106,457	$ 79,014
Total interest expense	10,326	10,150	9,779	8,893	8,651	7,935	7,742	7,338	39,148	31,666	26,367
Net interest income	24,111	21,823	19,255	19,687	19,743	18,992	18,039	18,017	84,876	74,791	52,647
Provision for loan losses	2,400	2,400	2,400	2,600	4,800	1,800	1,800	2,635	9,800	11,035	8,010
Net interest income after provision for loan losses	21,711	19,423	16,855	17,087	14,943	17,192	16,239	15,382	75,076	63,756	44,637
Noninterest income	5,400	2,461	2,738	2,817	4,757	1,558	3,968	2,853	967	1,073	515
Noninterest expense	19,422	17,092	15,185	15,633	13,820	13,586	13,863	13,738	67,332	55,007	36,247
Income before income taxes	7,689	4,792	4,408	4,271	5,880	5,164	6,344	4,497	21,160	21,885	14,341
Income tax (benefit) expense	(5,867)	(5,673)	(4,198)	(4,013)	443	(3,130)	(2,952)	(1,926)	(19,751)	(7,565)	(5,407)
Net income	13,556	10,465	8,606	8,284	5,437	8,294	9,296	6,423	40,911	29,450	19,748
Less net income attributable to noncontrolling interest	(62)	(62)	(95)	(95)	(375)	(17)		(118)		510	308
Net income attributable to Company	13,556	10,465	8,606	8,284	5,062	8,277	9,296	6,305	40,911	28,940	19,440
Less preferred stock dividends	(95)	(62)	(95)	(95)	(95)	(226)	(94)	(95)	(347)	(510)	(792)
Income available to common shareholders	$ 13,461	$ 10,403	$ 8,511	$ 8,189	$ 4,967	$ 8,051	$ 9,202	$ 6,210	$ 40,564	$ 28,430	$ 18,068
Earnings per common share-basic	$ 0.71	$ 0.55	$ 0.51	$ 0.59	$ 0.36	$ 0.58	$ 0.66	$ 0.45	$ 2.38	$ 2.04	$ 1.55
Earnings per common share-diluted	$ 0.69	$ 0.54	$ 0.49	$ 0.58	$ 0.35	$ 0.57	$ 0.65	$ 0.44	$ 2.32	$ 2.02	$ 1.54