Acquisitions (Detail) (USD $)	3 Months Ended			12 Months Ended											12 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Dec. 31, 2012	Sep. 30, 2011	Sep. 30, 2010	Apr. 20, 2012	Apr. 27, 2012 Commercial Loans And Commercial OREO [Member] Plantation Federal Bank [Member]	Apr. 27, 2012 Estimate of Fair Value, Fair Value Disclosure [Member] Plantation Federal Bank [Member]	Apr. 20, 2012 Perfoming Loans [Member] Liberty Savings Bank [Member]	Apr. 20, 2012 Business Acquisition Deposits [Member] Liberty Savings Bank [Member]	Apr. 20, 2012 Liberty Savings Bank [Member]	Apr. 20, 2012 Buildings [Member]	Apr. 20, 2012 Land Acquired [Member]	Dec. 31, 2012 Plantation Federal Bank [Member]
Business Acquisition, Cost of Acquired Entity, Transaction Costs							$ 500,000			$ 22,200,000	$ 113,200,000		$ 1,000,000	$ 500,000
Business Acquisition, Purchase Price Allocation, Intangible Assets Other than Goodwill												5,200,000
Cash Payment To First Federal															45,900,000
Business Acquisition, Purchase Price Allocation, Current Assets, Receivables								216,400,000	168,600,000
Percentage Of All Eligible Losses To Reimburse With Respect To Covered Assets															80.00%
Losses Incurred In First Federal Reimburse															55,000,000
Maximum Losses Absorbs By FDIC															65,000,000
Percentage Of All Eligible Losses In First Federal Reimburse															60.00%
Payments to Acquire Property, Plant, and Equipment	2,800,000		867,000	3,778,000	3,332,000	6,913,000
Business Acquisitions Estimated Amount Of Fixed Assets Acquire In Future	625,000
Business Combination, Bargain Purchase, Gain Recognized, Amount		$ 13,900,000