Stock-Based Compensation (Narrative) (Details)	3 Months Ended		6 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Sep. 30, 2024 USD ($) director shares	Sep. 30, 2023 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 1,400,000	$ 1,200,000			$ 3,000,000.0	$ 3,400,000
Stock-based compensation tax benefit	304,000	$ 278,000			$ 675,000	$ 798,000
Non-Employee Director Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of directors | director					12
Director equity grants granted, value				$ 37,500
Non-Employee Director Awards | Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Director equity grants granted, value			$ 37,500
Long-Term Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	4,400,000				$ 4,400,000
Unrecognized compensation expense, period for recognition					1 year 10 months 24 days
Long-Term Restricted Stock Awards | Next Twelve Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	2,900,000				$ 2,900,000
Long-Term Restricted Stock Awards | Remaining Quarters of 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 1,300,000				$ 1,300,000
First Bancorp 2014 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for grant | shares	1,929,731				1,929,731