Document and Entity Information - shares
6 Months Ended
Jun. 30, 2019
Aug. 02, 2019
Document Information [Line Items]    
Document Transition Report false  
Document Quarterly Report true  
Entity Address, Address Line One 14817 Oak Lane  
Entity Address, City or Town Miami Lakes  
Entity Address, State or Province FL  
Entity Address, Postal Zip Code 33016  
Entity Registrant Name BankUnited, Inc.  
Entity Central Index Key 0001504008  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jun. 30, 2019  
Entity File Number 001-35039  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Entity Common Stock Shares Outstanding   95,067,938
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Shell Company false  
Entity Shell Company DE  
Entity Tax Identification Number 27-0162450  
City Area Code 305  
Local Phone Number 569-2000   
Entity Small Business false  
Entity Emerging Growth Company false  
Document Information [Line Items]    
Title of 12(b) Security Common Stock, $0.01 Par Value  
Trading Symbol BKU  
Security Exchange Name NYSE