Loans - Summary of Impaired Loans by Loan Class (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	$ 19,989	$ 30,397
Impaired loans, Recorded Investment	42,141	47,660
Unpaid Principal Balance, With no related allowance recorded	24,820	38,297
Impaired loans, Unpaid Principal Balance	48,198	56,429
Related Allowance, With no related allowance recorded	0	0
Recorded Investment, With an allowance recorded	22,152	17,263
Unpaid Principal Balance, With an allowance recorded	23,378	18,132
Impaired loans, Related Allowance	4,994	2,301
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded		109
Impaired loans, Recorded Investment	6,590	3,458
Unpaid Principal Balance, With no related allowance recorded		109
Impaired loans, Unpaid Principal Balance	6,808	3,479
Related Allowance, With no related allowance recorded		0
Recorded Investment, With an allowance recorded	6,590	3,349
Unpaid Principal Balance, With an allowance recorded	6,808	3,370
Impaired loans, Related Allowance	2,988	1,051
Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans, Recorded Investment	21,747	29,077
Impaired loans, Unpaid Principal Balance	24,204	34,156
Impaired loans, Related Allowance	814	194
Residential [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans, Recorded Investment	13,804	15,125
Impaired loans, Unpaid Principal Balance	17,186	18,794
Impaired loans, Related Allowance	1,192	1,056
Commercial real estate: Other [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	15,736	24,479
Unpaid Principal Balance, With no related allowance recorded	18,184	29,558
Related Allowance, With no related allowance recorded	0	0
Recorded Investment, With an allowance recorded	6,011	4,598
Unpaid Principal Balance, With an allowance recorded	6,020	4,598
Impaired loans, Related Allowance	814	194
Residential: 1-4 family [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	3,714	5,809
Unpaid Principal Balance, With no related allowance recorded	6,091	8,630
Related Allowance, With no related allowance recorded	0	0
Recorded Investment, With an allowance recorded	8,805	8,755
Unpaid Principal Balance, With an allowance recorded	9,804	9,603
Impaired loans, Related Allowance	963	980
Residential: Home equities [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	539
Unpaid Principal Balance, With no related allowance recorded	545
Related Allowance, With no related allowance recorded	0
Recorded Investment, With an allowance recorded	746	561
Unpaid Principal Balance, With an allowance recorded	746	561
Impaired loans, Related Allowance	$ 229	$ 76