Loans, Allowance for Loan Losses, and Credit Quality Indicators - Aged Analysis of Dental Loans Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [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	11,940	29,959
Total Current	859,317	790,870
Total Loans Receivable	871,257	820,829
Commercial and other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing	264	634
60-89 Days Past Due Still Accruing
Greater Than 90 Days Still Accruing
Nonaccrual	4,315	5,999
Total Past Due and Nonaccrual	4,579	6,633
Total Current	322,137	267,523
Total Loans Receivable	326,716	274,156
Consumer loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing	8
Total Past Due and Nonaccrual	8
Total Current	3,573	4,569
Total Loans Receivable	3,581	4,569
Real estate loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing	1,755	402
60-89 Days Past Due Still Accruing	318	400
Nonaccrual	4,945	9,139
Total Past Due and Nonaccrual	7,018	9,941
Total Current	454,222	468,525
Total Loans Receivable	461,240	478,466
Real estate loans [Member] | Multi-family residential [Member]
Financing Receivable, Recorded Investment, Past Due [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	45,212	51,897
Total Loans Receivable	45,212	51,897
Real estate loans [Member] | Residential 1-4 family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing	351	251
60-89 Days Past Due Still Accruing	318	210
Nonaccrual	1,140	3,426
Total Past Due and Nonaccrual	1,809	3,887
Total Current	49,628	57,830
Total Loans Receivable	51,437	61,717
Real estate loans [Member] | Owner-occupied commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing		151
60-89 Days Past Due Still Accruing		190
Greater Than 90 Days Still Accruing
Nonaccrual	3,805	5,138
Total Past Due and Nonaccrual	3,805	5,479
Total Current	215,471	201,529
Total Loans Receivable	219,276	207,008
Real estate loans [Member] | Nonowner-occupied commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing	1,404
Nonaccrual		575
Total Past Due and Nonaccrual	1,404	575
Total Current	143,911	157,269
Total Loans Receivable	145,315	157,844
Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing	234	1,754
60-89 Days Past Due Still Accruing		175
Nonaccrual	101	11,456
Total Past Due and Nonaccrual	335	13,385
Total Current	79,385	50,253
Total Loans Receivable	79,720	63,638
Construction [Member] | Multi-family residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
60-89 Days Past Due Still Accruing
Greater Than 90 Days Still Accruing
Nonaccrual
Total Past Due and Nonaccrual
Total Current	17,022	2,574
Total Loans Receivable	17,022	2,574
Construction [Member] | Residential 1-4 family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing	234	67
Nonaccrual		757
Total Past Due and Nonaccrual	234	824
Total Current	20,156	17,136
Total Loans Receivable	20,390	17,960
Construction [Member] | Aged Analysis of Loans Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing		1,635
60-89 Days Past Due Still Accruing
Greater Than 90 Days Still Accruing
Nonaccrual		933
Total Past Due and Nonaccrual		2,568
Total Current	23,235	8,333
Total Loans Receivable	23,235	10,901
Construction [Member] | Commercial bare land and acquisition & development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		7,837
Total Past Due and Nonaccrual		7,837
Total Current	10,668	11,659
Total Loans Receivable	10,668	19,496
Construction [Member] | Residential bare land and acquisition & development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due Still Accruing		52
60-89 Days Past Due Still Accruing		175
Greater Than 90 Days Still Accruing
Nonaccrual	101	1,929
Total Past Due and Nonaccrual	101	2,156
Total Current	8,304	10,551
Total Loans Receivable	$ 8,405	$ 12,707