Loans and Other Repossessed Assets Acquired (Detail) - Troubled debt restructurings on nonaccrual status (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Still Accruing	$ 3,340	$ 2,411
Nonaccrual	14,333	13,775
Total	17,673	16,186
Residential Loans [Member] | Residential 1-4 Family [Member]
Still Accruing	328	734
Nonaccrual	4,458	1,269
Total	4,786	2,003
Residential Loans [Member] | Residential Land [Member]
Still Accruing	0	0
Nonaccrual	66	0
Total	66	0
Residential Loans [Member]
Still Accruing	328	734
Nonaccrual	4,524	1,269
Total	4,852	2,003
Commercial Loan [Member] | Commercial Business [Member]
Still Accruing	689	700
Nonaccrual	0	1,113
Total	689	1,813
Commercial Loan [Member] | Commercial Real Estate [Member]
Still Accruing	1,512	977
Nonaccrual	3,475	5,293
Total	4,987	6,270
Commercial Loan [Member] | Commercial Land [Member]
Still Accruing	499	0
Nonaccrual	1,727	2,192
Total	2,226	2,192
Commercial Loan [Member]
Still Accruing	2,700	1,677
Nonaccrual	5,202	8,598
Total	7,902	10,275
Consumer Loan [Member] | Home Equity Loans [Member]
Still Accruing	176	0
Nonaccrual	4,607	3,775
Total	4,783	3,775
Consumer Loan [Member] | Manufactured Housing [Member]
Still Accruing	136	0
Nonaccrual	0	133
Total	136	133
Consumer Loan [Member]
Still Accruing	312	0
Nonaccrual	4,607	3,908
Total	$ 4,919	$ 3,908