LOAN PORTFOLIO - Loan Portfolio Held for Investment (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013
Financial Information [Line Items]
Residential mortgage loans, mainly secured by first mortgages	$ 2,819,648		$ 2,549,008
Commercial loans:
Construction loans	141,689		168,713
Commercial mortgage loans	1,812,094		1,823,608
Commercial and Industrial loans	2,515,384	[1]	2,788,250	[1]
Loans to local financial institutions collateralized by real estate mortgages	0	[2]	240,072	[2]
Commercial loans	4,469,167		5,020,643
Finance leases	236,115		245,323
Consumer loans	1,790,472		1,821,196
Loans held for investment	9,315,402		9,636,170		9,508,634
Less: allowance for loan and lease losses	(225,434)		(285,858)
Loans held for investment, net	9,089,968		9,350,312
Commercial And Industrial [Member]
Commercial loans:
Loans held for investment	$ 2,515,384		$ 3,028,322

[1] As of September 30, 2014 and December 31, 2013, includes $1.1 billion and $1.2 billion, respectively, of commercial loans that are secured by real estate but are not dependent upon the real estate for repayment.

[2] On May 30, 2014, FirstBank acquired from Doral Financial Corporation ("Doral") mortgage loans, mainly residential mortgage loans, having an unpaid principal balance of $241.7 million (estimated fair value at acquisition of $226.0 million) in full satisfaction of secured borrowings with a book value of $232.9 million owed by Doral to FirstBank. Refer to Acquired Loans, including Purchased Credit-Impaired ("PCI") loans discussion below for additional information.