FIRST BANCORP. (Holding Company Only) Financial Information - Statements of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 102,273	$ 167,377	$ 201,608
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	5,117	3,949	5,825
Gain on early extinguishment of debt	(94)	0	(2,316)
Net (increase) decrease in other assets	(5,018)	32,521	8,906
Net (decrease) increase in other liabilities	9,116	(4,590)	(1,521)
Net cash provided by operating activities	297,738	294,284	288,323
Cash flows from investing activities:
Net cash provided by investing activities	(1,238,865)	(342,968)	(223,258)
Cash flows from financing activities:
Repurchase of common stock	(206)	(1,959)	(2,827)
Dividends paid on common stock	(43,416)	(30,356)	(6,517)
Dividends paid on preferred stock	(2,676)	(2,676)	(2,676)
Net cash used in financing activities	1,790,861	106,580	(195,257)
Cash and cash equivalents at beginning of year	644,099	586,203	716,395
Cash and cash equivalents at end of year	1,493,833	644,099	586,203
Cash and cash equivalents include:
Money market instruments	60,572	97,708	7,590
Holding Company [Member]
Cash flows from operating activities:
Net income	102,273	167,377	201,608
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	231	314	2,202
Equity in undistributed earnings of subsidiaries	(59,843)	(138,925)	(172,580)
Gain on early extinguishment of debt	(94)	0	(2,316)
Accretion of discount on loans	0	0	(4)
Net (increase) decrease in other assets	(1,514)	11,710	(8,417)
Net (decrease) increase in other liabilities	(459)	526	2,890
Net cash provided by operating activities	40,594	41,002	23,383
Cash flows from investing activities:
Principal collected on loans	0	0	191
Net cash provided by investing activities	0	0	191
Cash flows from financing activities:
Repurchase of common stock	(206)	(1,959)	(2,827)
Repayments of junior subordinated debentures	(282)	0	(21,434)
Dividends paid on common stock	(43,416)	(30,356)	(6,517)
Dividends paid on preferred stock	(2,676)	(2,676)	(2,676)
Net cash used in financing activities	(46,580)	(34,991)	(33,454)
Net increase (decrease) in cash and cash equivalents	(5,986)	6,011	(9,880)
Cash and cash equivalents at beginning of year	23,106	17,095	26,975
Cash and cash equivalents at end of year	17,120	23,106	17,095
Cash and cash equivalents include:
Cash and due from banks	10,909	16,895	10,984
Money market instruments	$ 6,211	$ 6,211	$ 6,111