Loans Receivable and Allowance for Loan Losses - Activity in Allowance for Loan Losses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	$ 20,425	$ 20,098	$ 20,965	$ 23,166
Provision for loan losses	(2,900)	0	(2,900)	(1,400)
Charge-offs	(2,238)	(1,815)	(3,340)	(5,059)
Recoveries	732	2,969	1,294	4,545
Balance, end of period	16,019	21,252	16,019	21,252
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	14,053	11,288	13,215	13,719
Provision for loan losses	(2,593)	3,495	(1,210)	3,653
Charge-offs	(1,840)	(1,767)	(2,514)	(4,444)
Recoveries	382	45	511	133
Balance, end of period	10,002	13,061	10,002	13,061
Acquisition and Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	852	1,946	670	3,502
Provision for loan losses	(284)	(1,117)	(73)	(3,943)
Charge-offs	(33)	(2)	(67)	(146)
Recoveries	0	267	5	1,681
Balance, end of period	535	1,094	535	1,094
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	993	875	864	1,635
Provision for loan losses	(387)	(2,651)	(552)	(3,309)
Charge-offs	(1)	0	(64)	(114)
Recoveries	317	2,530	674	2,542
Balance, end of period	922	754	922	754
Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	178	254	244	223
Provision for loan losses	9	(12)	(57)	19
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	187	242	187	242
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	16,076	14,363	14,993	19,079
Provision for loan losses	(3,255)	(285)	(1,892)	(3,580)
Charge-offs	(1,874)	(1,769)	(2,645)	(4,704)
Recoveries	699	2,842	1,190	4,356
Balance, end of period	11,646	15,151	11,646	15,151
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	2,362	3,796	3,780	2,275
Provision for loan losses	72	2	(1,150)	1,750
Charge-offs	(286)	0	(495)	(263)
Recoveries	6	100	19	136
Balance, end of period	2,154	3,898	2,154	3,898
Installment and Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	186	134	124	85
Provision for loan losses	66	11	192	80
Charge-offs	(78)	(46)	(200)	(92)
Recoveries	27	27	85	53
Balance, end of period	201	126	201	126
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	2,548	3,930	3,904	2,360
Provision for loan losses	138	13	(958)	1,830
Charge-offs	(364)	(46)	(695)	(355)
Recoveries	33	127	104	189
Balance, end of period	2,355	4,024	2,355	4,024
Unallocated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Balance, beginning of period	1,801	1,805	2,068	1,727
Provision for loan losses	217	272	(50)	350
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	$ 2,018	$ 2,077	$ 2,018	$ 2,077