Dental Loan Portfolio - Aged Analysis of Dental Loans Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due Still Accruing	$ 2,261	$ 2,790
60-89 Days Past Due Still Accruing	318	575
Greater Than 90 Days Still Accruing
Nonaccrual	9,361	26,594
Total Past Due and Nonaccrual	2,499	1,378
Total Current	859,317	790,870
Total Loans Receivable	270,782	208,489
In Market [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	191,908	166,133
Out-of-Market [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Receivable	78,874	42,356
Dental Construction Loans [Member] | In Market [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due Still Accruing		634
60-89 Days Past Due Still Accruing
Greater Than 90 Days Still Accruing
Nonaccrual	2,499	744
Total Past Due and Nonaccrual	2,499	1,378
Total Current	189,409	164,755
Total Loans Receivable	191,908	166,133
Dental Construction Loans [Member] | Out-of-Market [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due Still Accruing
60-89 Days Past Due Still Accruing
Greater Than 90 Days Still Accruing
Nonaccrual
Total Past Due and Nonaccrual
Total Current	78,874	42,356
Total Loans Receivable	$ 78,874	$ 42,356