Loans - Summary of Credit Quality Indicators on Company's Loan Portfolio (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 2,357,777	$ 1,922,217
Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	212,430	168,544
Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,128,181	988,994
Consumer real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	117,653	103,516
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	883,111	647,090
Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	16,402	14,073
Pass and Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,274,125	1,845,486
Pass and Pass/Watch [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	197,951	146,748
Pass and Pass/Watch [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,073,339	962,694
Pass and Pass/Watch [Member] | Consumer real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	113,037	101,334
Pass and Pass/Watch [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	873,547	620,851
Pass and Pass/Watch [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	16,251	13,859
Special Mention Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,935	5,738
Special Mention Loans [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4	3,258
Special Mention Loans [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,720	1,698
Special Mention Loans [Member] | Consumer real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	185	751
Special Mention Loans [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	17	18
Special Mention Loans [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9	13
Substandard Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	81,717	59,756
Substandard Loans [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	14,475	18,538
Substandard Loans [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	53,122	24,602
Substandard Loans [Member] | Consumer real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,431	1,431
Substandard Loans [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,547	14,984
Substandard Loans [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	142	201
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	11,237
Doubtful [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Doubtful [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Doubtful [Member] | Consumer real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Doubtful [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	11,237
Doubtful [Member] | Other consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0