FIRST BANCORP. (Holding Company Only) Financial Information - Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income:
Interest income on money market investments	$ 102,505	$ 102,922	$ 72,893
Gain on early extinguishment of debt	1,605	0	0
Expense:
Income tax expense	94,572	142,512	146,792
Net income	302,864	305,072	281,025
Other comprehensive income (loss), net of tax	165,608	(720,779)	(139,454)
Comprehensive income (loss)	468,472	(415,707)	141,571
Holding Company [Member]
Income:
Interest income on money market investments	228	79	51
Gain on early extinguishment of debt	1,605	0	0
Other income	406	248	154
Total income	333,922	368,997	128,265
Expense:
Interest expense on long-term borrowings	13,535	8,253	5,135
Other non-interest expenses	1,817	1,730	1,929
Total expenses	15,352	9,983	7,064
Income before income taxes and equity in undistributed earnings of subsidiaries	318,570	359,014	121,201
Income tax expense	3,126	3,448	2,854
Equity in undistributed earnings of subsidiaries (distributions in excess of earnings)	(12,580)	(50,494)	162,678
Net income	302,864	305,072	281,025
Other comprehensive income (loss), net of tax	165,608	(720,779)	(139,454)
Comprehensive income (loss)	468,472	(415,707)	141,571
Holding Company [Member] | Investment In Banking Subsidiary [Member]
Income:
Dividend income	319,683	368,670	98,060
Holding Company [Member] | Non Banking Subsidiary [Member]
Income:
Dividend income	$ 12,000	$ 0	$ 30,000