FIRST BANCORP. (Holding Company Only) Financial Information - Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income:
Interest income on money market investments	$ 60,224	$ 51,125	$ 50,905
Interest income on loans	553,647	532,684	531,022
Total interest and dividends on investments	71,320	55,739	54,270
Expense:
Gains Losses On Extinguishment Of Debt	2,316	1,391	4,217
Income tax expense	10,970	4,973	(37,030)
Net income	201,608	66,956	93,229
Other comprehensive (loss) income, net of tax	(19,806)	13,775	(6,641)
Comprehensive income	181,802	80,731	86,588
Holding Company [Member]
Income:
Interest income on money market investments	20	20	20
Interest income on loans	105	0	0
Other Interest And Dividend Income	275	262	241
Total interest and dividends on investments	38,184	10,482	42,137
Expense:
Other borrowings	8,983	8,284	7,705
Other operating expenses	2,489	3,175	3,481
Total operating expenses	11,472	11,459	11,186
Gains Losses On Extinguishment Of Debt	2,316	1,391	4,217
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	29,028	414	35,168
Income tax expense	0	45	0
Equity in undistributed earnings of subsidiaries	172,580	66,587	58,061
Net income	201,608	66,956	93,229
Other comprehensive (loss) income, net of tax	(19,806)	13,775	(6,641)
Comprehensive income	181,802	80,731	86,588
Investment In Banking Subsidiary [Member] | Holding Company [Member]
Income:
Dividend income	37,784	7,200	34,876
Non Banking Subsidiary [Member] | Holding Company [Member]
Income:
Dividend income	$ 0	$ 3,000	$ 7,000