Loans - Age Analysis of Loan Portfolio, Segregated by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of Days Past Due, 30-59	$ 13,540	$ 17,932
Number of Days Past Due, 60-89	1,427	5,406
Number of Days Past Due, Greater Than 90	17,590	19,629
Number of Days Past Due, Total Past Due	32,557	42,967
Current	370,541	388,116
Total	403,098	431,083
Loans Past Due Greater Than 90 Days & Still Accruing	1,713	1,445
Gaming [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of Days Past Due, 30-59
Number of Days Past Due, 60-89		1,721
Number of Days Past Due, Greater Than 90
Number of Days Past Due, Total Past Due		1,721
Current	50,337	58,466
Total	50,337	60,187
Loans Past Due Greater Than 90 Days & Still Accruing
Residential and land development [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of Days Past Due, 30-59
Number of Days Past Due, 60-89
Number of Days Past Due, Greater Than 90	5,304	5,765
Number of Days Past Due, Total Past Due	5,304	5,765
Current	21,779	21,573
Total	27,083	27,338
Loans Past Due Greater Than 90 Days & Still Accruing
Real estate, construction [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of Days Past Due, 30-59	1,474	3,989
Number of Days Past Due, 60-89		878
Number of Days Past Due, Greater Than 90	4,334	6,151
Number of Days Past Due, Total Past Due	5,808	11,018
Current	44,139	41,568
Total	49,947	52,586
Loans Past Due Greater Than 90 Days & Still Accruing	424	572
Real estate, mortgage [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of Days Past Due, 30-59	8,080	12,012
Number of Days Past Due, 60-89	1,424	2,702
Number of Days Past Due, Greater Than 90	7,924	7,605
Number of Days Past Due, Total Past Due	17,428	22,319
Current	215,730	224,101
Total	233,158	246,420
Loans Past Due Greater Than 90 Days & Still Accruing	1,261	872
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of Days Past Due, 30-59	3,930	1,804
Number of Days Past Due, 60-89		79
Number of Days Past Due, Greater Than 90		107
Number of Days Past Due, Total Past Due	3,930	1,990
Current	30,409	33,014
Total	34,339	35,004
Loans Past Due Greater Than 90 Days & Still Accruing
Other [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Number of Days Past Due, 30-59	56	127
Number of Days Past Due, 60-89	3	26
Number of Days Past Due, Greater Than 90	28	1
Number of Days Past Due, Total Past Due	87	154
Current	8,147	9,394
Total	8,234	9,548
Loans Past Due Greater Than 90 Days & Still Accruing	$ 28	$ 1