FIRST BANCORP. (Holding Company Only) Financial Information - Statements of Financial Condition (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
ASSETS
Cash and due from banks	$ 786,788	$ 206,897
Money market investments	216,932	239,669	187,674
Investment securities available for sale, at market:
Other investment securities	527,472	756,003
Other assets	242,292	235,601
Total assets	13,139,747	13,127,275
Liabilities:
Other borrowings	231,959	231,959
Accounts payable and other liabilities	108,829	152,636
Total liabilities	11,655,630	11,683,131
Total liabilities and stockholders' equity	13,139,747	13,127,275
First Bank Puerto Rico [Member]
Investment securities available for sale, at market:
Investment in First Bank Puerto Rico, at equity	1,660,373	1,615,304
First Bank Insurance Agency [Member]
Investment securities available for sale, at market:
Investment in First Bank Insurance Agency, at equity	7,163	5,338
FBP Statutory Trust I [Member]
Investment securities available for sale, at market:
Investment in FBP Statutory Trust I	3,093	3,093
FBP Statutory Trust II [Member]
Investment securities available for sale, at market:
Investment in FBP Statutory Trust II	3,866	3,866
Holding Company [Member]
ASSETS
Cash and due from banks	36,631	41,681
Money market investments	6,111	3,111
Investment securities available for sale, at market:
Equity investments	40	41
Other investment securities	1,300	1,300
Other assets	3,669	3,488
Total assets	1,722,246	1,677,222
Liabilities:
Other borrowings	231,959	231,959
Accounts payable and other liabilities	6,170	1,119
Total liabilities	238,129	233,078
Total liabilities and stockholders' equity	$ 1,722,246	$ 1,677,222