Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2021

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, 2021
Leverage Ratio
S&T	$	889,785	9.74	%	$	365,535	4.00	%	$	456,918	5.00	%
S&T Bank	864,127		9.46	%	365,544		4.00	%	456,930		5.00	%
Common Equity Tier 1 (to Risk-Weighted Assets)
S&T	860,785		12.03	%	322,109		4.50	%	465,268		6.50	%
S&T Bank	864,127		12.09	%	321,711		4.50	%	464,694		6.50	%
Tier 1 Capital (to Risk-Weighted Assets)
S&T	889,785		12.43	%	429,479		6.00	%	572,638		8.00	%
S&T Bank	864,127		12.09	%	428,948		6.00	%	571,931		8.00	%
Total Capital (to Risk-Weighted Assets)
S&T	987,420		13.79	%	572,638		8.00	%	715,798		10.00	%
S&T Bank	961,762		13.45	%	571,931		8.00	%	714,913		10.00	%
As of December 31, 2020
Leverage Ratio
S&T	$	852,515	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	%