Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2020

Regulatory Capital Requirements Under Banking Regulations [Abstract]

Summary of Risk-Based Capital Amounts and Ratios

The following table summarizes risk-based capital amounts and ratios for S&T and S&T Bank:

	Actual				Minimum Regulatory Capital Requirements				To be Well Capitalized Under Prompt Corrective Action Provisions
(dollars in thousands)	Amount		Ratio		Amount		Ratio		Amount		Ratio
As of December 31, 2020
Leverage Ratio
S&T	$	825,515	9.43 %		$	350,311	4.00 %		$	437,889	5.00 %
S&T Bank	810,636		9.27 %		349,739		4.00 %		437,174		5.00 %
Common Equity Tier 1 (to Risk-Weighted Assets)
S&T	796,515		11.33 %		316,338		4.50 %		456,933		6.50 %
S&T Bank	810,636		11.55 %		315,792		4.50 %		456,144		6.50 %
Tier 1 Capital (to Risk-Weighted Assets)
S&T	825,515		11.74 %		421,784		6.00 %		562,379		8.00 %
S&T Bank	810,636		11.55 %		421,056		6.00 %		561,408		8.00 %
Total Capital (to Risk-Weighted Assets)
S&T	944,686		13.44 %		562,379		8.00 %		702,974		10.00 %
S&T Bank	922,007		13.14 %		561,408		8.00 %		701,760		10.00 %
As of December 31, 2019
Leverage Ratio
S&T	$	854,146	10.29	%	$	331,925	4.00	%	$	414,907	5.00	%
S&T Bank	832,113		10.04	%	331,355		4.00	%	414,194		5.00	%
Common Equity Tier 1 (to Risk-Weighted Assets)
S&T	825,146		11.43	%	324,745		4.50	%	469,077		6.50	%
S&T Bank	832,113		11.56	%	324,048		4.50	%	468,069		6.50	%
Tier 1 Capital (to Risk-Weighted Assets)
S&T	854,146		11.84	%	432,994		6.00	%	577,325		8.00	%
S&T Bank	832,113		11.56	%	432,064		6.00	%	576,085		8.00	%
Total Capital (to Risk-Weighted Assets)
S&T	954,094		13.22	%	577,325		8.00	%	721,656		10.00	%
S&T Bank	922,310		12.81	%	576,085		8.00	%	720,106		10.00	%