CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Treasury Stock
Balance at beginning of period at Dec. 31, 2022	$ 1,184,659	$ (447)	$ 103,623	$ 406,283	$ 863,948	$ (447)	$ (112,125)	$ (77,070)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	144,781				144,781
Other comprehensive income, net of tax	21,224						21,224
Cash dividends declared	(49,850)				(49,850)
Treasury stock issued for restricted stock awards	0			(1,123)				1,123
Forfeitures of restricted stock awards	(798)				1,172			(1,970)
Repurchase of S&T Stock	(19,998)							(19,998)
Recognition of restricted stock compensation expense	3,874			3,874
Balance at end of period at Dec. 31, 2023	1,283,445	$ (1,002)	103,623	409,034	959,604	$ (1,002)	(90,901)	(97,915)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	131,265				131,265
Other comprehensive income, net of tax	13,909						13,909
Cash dividends declared	(51,075)				(51,075)
Treasury stock issued for restricted stock awards	0			(1,871)				1,871
Forfeitures of restricted stock awards	(870)				243			(1,113)
Recognition of restricted stock compensation expense	4,622			4,622
Balance at end of period at Dec. 31, 2024	1,380,294		103,623	411,785	1,039,035		(76,992)	(97,157)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	134,230				134,230
Other comprehensive income, net of tax	35,285						35,285
Cash dividends declared	(52,968)				(52,968)
Treasury stock issued for restricted stock awards	0			(4,160)				4,160
Forfeitures of restricted stock awards	(1,672)							(1,672)
Repurchase of S&T Stock	(36,636)							(36,636)
Recognition of restricted stock compensation expense	5,344			5,344
Balance at end of period at Dec. 31, 2025	$ 1,463,877		$ 103,623	$ 412,969	$ 1,120,297		$ (41,707)	$ (131,305)