XML 86 R58.htm IDEA: XBRL DOCUMENT v3.20.1
Allowance for Credit Losses - Additional Information (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2020
Jan. 01, 2020
Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]      
Adjustment to allowance for credit loss $ 96,850 $ 62,224 $ 62,224
ACL provision, COVID-19 assessment 14,900    
ACL provision, COVID-19 assessment, revised forecast 11,200    
ACL provision, COVID-19 assessment, changes in current conditions $ 3,700    
Impact of ASU 2016-13 Adoption      
Financing Receivable, Allowance for Credit Loss [Line Items]      
Adjustment to allowance for credit loss   27,353 $ 27,352
S&T Legacy Loans | Impact of ASU 2016-13 Adoption      
Financing Receivable, Allowance for Credit Loss [Line Items]      
Adjustment to allowance for credit loss   8,200  
Commercial and industrial | Impact of ASU 2016-13 Adoption      
Financing Receivable, Allowance for Credit Loss [Line Items]      
Adjustment to allowance for credit loss   9,900  
DNB | Impact of ASU 2016-13 Adoption      
Financing Receivable, Allowance for Credit Loss [Line Items]      
Adjustment to allowance for credit loss   $ 9,300