FIRST BANCORP. (Holding Company Only) Financial Information - Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income:
Interest income on money market investments	$ 58,547	$ 59,546	$ 60,224
Interest income on loans	631,047	602,998	553,647
Total interest and dividends on investments	61,935	72,899	71,320
Expense:
Gain on early extinguishment of debt	94	0	2,316
Total income tax provision	14,050	71,995	(10,970)
Net income	102,273	167,377	201,608
OCI, net of tax	48,691	47,179	(19,806)
Comprehensive income	150,964	214,556	181,802
Holding Company [Member]
Income:
Interest income on money market investments	71	233	20
Interest income on loans	0	0	105
Other Interest And Dividend Income	439	283	275
Total interest and dividends on investments	53,217	42,759	38,184
Expense:
Other borrowings	6,355	9,424	8,983
Other operating expenses	2,097	2,131	2,489
Total operating expenses	8,452	11,555	11,472
Gain on early extinguishment of debt	94	0	2,316
Income before income taxes and equity in undistributed earnings of subsidiaries	44,859	31,204	29,028
Total income tax provision	2,429	2,752	0
Equity in undistributed earnings of subsidiaries	59,843	138,925	172,580
Net income	102,273	167,377	201,608
OCI, net of tax	48,691	47,179	(19,806)
Comprehensive income	150,964	214,556	181,802
Investment In Banking Subsidiary [Member] | Holding Company [Member]
Income:
Dividend income	$ 52,707	$ 42,243	$ 37,784