XML 27 R1.htm IDEA: XBRL DOCUMENT v3.7.0.1
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2017
Aug. 02, 2017
Document and Entity Information    
Entity Registrant Name SENIOR HOUSING PROPERTIES TRUST  
Entity Central Index Key 0001075415  
Document Type 10-Q  
Document Period End Date Jun. 30, 2017  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding (in shares)   237,558,963
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q2