XML 12 R1.htm IDEA: XBRL DOCUMENT v3.21.2
Document and Entity Information - shares
3 Months Ended
Sep. 30, 2021
Nov. 02, 2021
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2021  
Document Fiscal Year Focus 2022  
Document Fiscal Period Focus Q1  
Trading Symbol PCSB  
Entity Registrant Name PCSB Financial Corporation  
Entity Central Index Key 0001691337  
Current Fiscal Year End Date --06-30  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period true  
Entity Common Stock, Shares Outstanding   15,522,239
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Shell Company false  
Title of 12(b) Security Common Stock, $0.01 par value per share  
Security Exchange Name NASDAQ  
Entity File Number 001-38065  
Entity Incorporation, State or Country Code MD  
Entity Tax Identification Number 81-4710738  
Entity Address, Address Line One 2651 Strang Blvd  
Entity Address, Address Line Two Suite 100  
Entity Address, City or Town Yorktown Heights  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10598  
City Area Code 914  
Local Phone Number 248-7272  
Document Quarterly Report true  
Document Transition Report false