NON-CONSOLIDATED VARIABLE INTEREST ENTITIES AND SERVICING ASSETS - additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended			9 Months Ended
	Feb. 16, 2011	Sep. 30, 2004	Apr. 30, 2004	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2016	Sep. 30, 2015
Servicing Liabilities At Fair Value [Line Items]
Principal amount of corporation serviced loans securitized through GNMA				$ 1,400,000			$ 1,400,000
Balance of amortization with third party				30,600			30,600
Carrying value with third party				$ 22,100			22,100
Percentage of weighted average yield with third party				2.37%
Working capital line of credit to fund certain expenses	$ 20,000
Payment to be made on pro rata basis				65.00%
Debt Instrument Description Of Variable Rate Basis				90-day LIBOR
Interest Expense Accrued Trust Preferred Securities					$ 31,200
Conversion Of Stock Shares Issued1					852,831
Common Stock Issued In Exchange For Trust Preferred Securities Value							0	$ 5,628
Trust Preferred Securities Exchanged Liquidation Value					$ 5,300		0	$ 5,303
Trust Preferred Securities Repurchases						$ 10,000
Trust Preferred Securties Discount						30.00%
Trust Preferred Securities Winning Bid						70.00%
Common Stock Issued In Exchange For Trust Preferred Securities Additional Paid In Capital Value					$ 5,500
Maximum [Member]
Servicing Liabilities At Fair Value [Line Items]
Percentage of variation in assumptions				20.00%
Minimum [Member]
Servicing Liabilities At Fair Value [Line Items]
Percentage of variation in assumptions				10.00%
Fbp Statutory Trust One [Member]
Servicing Liabilities At Fair Value [Line Items]
Variable rate trust preferred securities			$ 100,000
Proceeds of the issuance, together with proceeds of the purchase			3,100
Principal amount of corporation's junior subordinated deferrable debentures			$ 103,100
Fbp Statutory Trust Two [Member]
Servicing Liabilities At Fair Value [Line Items]
Variable rate trust preferred securities		$ 125,000
Proceeds of the issuance, together with proceeds of the purchase		3,900
Principal amount of corporation's junior subordinated deferrable debentures		$ 128,900
Cpg Gs [Member]
Servicing Liabilities At Fair Value [Line Items]
Loans Sold to CPG	269,300
Cash realized on sale of loan	88,500
Loans acquired on exchange of loan held for sale	$ 136,100
Description of loan	30-day LIBOR plus 300 basis points
Carrying amount of loan provided				$ 6,800			6,800
Line of credit facility provided to fund unfunded commitments	$ 80,000
Revolver agreement of credit facility provided amount outstanding				$ 11,400			$ 11,400
Prlp [Member]
Servicing Liabilities At Fair Value [Line Items]
Percentage of ownership investment in unconsolidated entity	65.00%
Percentage of priority interest to be received on invested capital				12.00%
Payment to be made on pro rata basis				35.00%
FirstBank [Member]
Servicing Liabilities At Fair Value [Line Items]
Acquired Equity interest on disposal of loans held for sale	35.00%