Allowance for Loan Losses - Non Homogenous Loans and Leases (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	$ 312,036	$ 286,778
Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	22,266	13,815
Land, Farmland, Ag Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	17,108	14,002
Commercial and Non-Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	139,538	136,879
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	54,871	42,094
Multi Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	78,253	79,988
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	271,841	235,522
Pass [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	16,760	10,586
Pass [Member] | Land, Farmland, Ag Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	15,570	13,063
Pass [Member] | Commercial and Non-Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	115,793	107,065
Pass [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	54,741	39,666
Pass [Member] | Multi Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	68,977	65,142
Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	22,588	30,370
Watch [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	5,496	3,215
Watch [Member] | Land, Farmland, Ag Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	775	0
Watch [Member] | Commercial and Non-Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	11,951	17,137
Watch [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	14	2,256
Watch [Member] | Multi Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	4,352	7,762
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	9,079	9,888
Special Mention [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	0	0
Special Mention [Member] | Land, Farmland, Ag Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	0	0
Special Mention [Member] | Commercial and Non-Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	7,563	6,479
Special Mention [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	0	0
Special Mention [Member] | Multi Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	1,516	3,409
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	8,528	10,998
Substandard [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	10	14
Substandard [Member] | Land, Farmland, Ag Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	763	939
Substandard [Member] | Commercial and Non-Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	4,231	6,198
Substandard [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	116	172
Substandard [Member] | Multi Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-homogenous loans and leases	$ 3,408	$ 3,675