CONCOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Dividends declared per share (in dollars per share)	$ 0.27	$ 0.22
Repurchase of S&T Stock (in shares)	313,904
Retained Earnings
Dividends declared per share (in dollars per share)	$ 0.27	$ 0.22
Treasury stock issued for restricted awards, net of forfeitures (in shares)		66,165
Forfeitures of restricted stock (in shares)	39,834	37,592
Treasury Stock
Repurchase of S&T Stock (in shares)	313,904