Loans - Impaired Loans, Segregated by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	$ 29,347	$ 51,863
With no related allowance recorded, Recorded Investment	28,722	50,668
With no related allowance recorded, Related Allowance
With no related allowance recorded, Average Recorded Investment	30,074	50,602
With no related allowance recorded, Interest Income Recognized	34	23
With a related allowance recorded, Unpaid Principal Balance	33,296	14,682
With a related allowance recorded, Recorded Investment	31,648	14,074
With a related allowance recorded, Related Allowance	6,603	3,074
With a related allowance recorded, Average Investment	31,245	11,863
With a related allowance recorded, Interest Income Recognized	151	327
Total by class of loans, Unpaid Principal Balance	62,643	66,545
Total by class of loans, Recorded Investment	60,370	64,742
Total by class of loans, Related Allowance	6,603	3,074
Total by class of loans, Average Investment	61,319	62,465
Total by class of loans, Interest Income Recognized	185	350
Gaming [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	10,933	14,528
With no related allowance recorded, Recorded Investment	10,933	14,528
With no related allowance recorded, Related Allowance
With no related allowance recorded, Average Recorded Investment	12,150	14,869
With a related allowance recorded, Unpaid Principal Balance	1,714	1,721
With a related allowance recorded, Recorded Investment	1,239	1,721
With a related allowance recorded, Related Allowance	626	1,100
With a related allowance recorded, Average Investment	1,403
Total by class of loans, Unpaid Principal Balance	12,647	16,249
Total by class of loans, Recorded Investment	12,172	16,249
Total by class of loans, Related Allowance	626	1,100
Total by class of loans, Average Investment	13,553	14,869
Residential and land development [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	4,468	21,837
With no related allowance recorded, Recorded Investment	4,468	20,733
With no related allowance recorded, Related Allowance
With no related allowance recorded, Average Recorded Investment	4,496	21,288
With a related allowance recorded, Unpaid Principal Balance	17,606	350
With a related allowance recorded, Recorded Investment	16,503	350
With a related allowance recorded, Related Allowance	3,143	70
With a related allowance recorded, Average Investment	16,555	350
Total by class of loans, Unpaid Principal Balance	22,074	22,187
Total by class of loans, Recorded Investment	20,971	21,083
Total by class of loans, Related Allowance	3,143	70
Total by class of loans, Average Investment	21,051	21,638
Real estate, construction [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	3,498	4,635
With no related allowance recorded, Recorded Investment	3,472	4,580
With no related allowance recorded, Related Allowance
With no related allowance recorded, Average Recorded Investment	3,519	3,833
With no related allowance recorded, Interest Income Recognized	13
With a related allowance recorded, Unpaid Principal Balance	2,410	1,694
With a related allowance recorded, Recorded Investment	2,374	1,686
With a related allowance recorded, Related Allowance	1,132	663
With a related allowance recorded, Average Investment	2,410	1,314
With a related allowance recorded, Interest Income Recognized	11	8
Total by class of loans, Unpaid Principal Balance	5,908	6,329
Total by class of loans, Recorded Investment	5,846	6,266
Total by class of loans, Related Allowance	1,132	663
Total by class of loans, Average Investment	5,929	5,147
Total by class of loans, Interest Income Recognized	24	8
Real estate, mortgage [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	9,758	9,971
With no related allowance recorded, Recorded Investment	9,159	9,935
With no related allowance recorded, Related Allowance
With no related allowance recorded, Average Recorded Investment	9,213	9,821
With no related allowance recorded, Interest Income Recognized	10
With a related allowance recorded, Unpaid Principal Balance	11,566	10,893
With a related allowance recorded, Recorded Investment	11,532	10,293
With a related allowance recorded, Related Allowance	1,702	1,229
With a related allowance recorded, Average Investment	10,877	10,199
With a related allowance recorded, Interest Income Recognized	140	319
Total by class of loans, Unpaid Principal Balance	21,324	20,864
Total by class of loans, Recorded Investment	20,691	20,228
Total by class of loans, Related Allowance	1,702	1,229
Total by class of loans, Average Investment	20,090	20,020
Total by class of loans, Interest Income Recognized	150	319
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Unpaid Principal Balance	690	892
With no related allowance recorded, Recorded Investment	690	892
With no related allowance recorded, Related Allowance
With no related allowance recorded, Average Recorded Investment	696	791
With no related allowance recorded, Interest Income Recognized	11	23
With a related allowance recorded, Unpaid Principal Balance		24
With a related allowance recorded, Recorded Investment		24
With a related allowance recorded, Related Allowance		12
Total by class of loans, Unpaid Principal Balance	690	916
Total by class of loans, Recorded Investment	690	916
Total by class of loans, Related Allowance		12
Total by class of loans, Average Investment	696	791
Total by class of loans, Interest Income Recognized	$ 11	$ 23