Entity Address, Address Line Three Entity Address, Address Line Three Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line Two Entity Address, Address Line Two Entity File Number Entity File Number Cover [Abstract] Cover [Abstract] Title of 12(b) Security Title of 12(b) Security Entities [Table] Entities [Table] Local Phone Number Local Phone Number Class of Stock [Domain] Class of Stock [Domain] Soliciting Material Soliciting Material Entity Address, Address Line One Entity Address, Address Line One Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Entity Address, State or Province Entity Address, State or Province Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Written Communications Written Communications Entity Information [Line Items] Entity Information [Line Items] Trading Symbol Trading Symbol 6.375% Senior Notes due 2050 Six Point Three Seven Five Percent Senior Notes Due 2050 [Member] Six Point Three Seven Five Percent Senior Notes Due 2050 [Member] City Area Code City Area Code Document Period End Date Document Period End Date Amendment Flag Amendment Flag Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Entity Address, City or Town Entity Address, City or Town Security Exchange Name Security Exchange Name Common Shares Of Beneficial Interest Common Shares Of Beneficial Interest [Member] Common Shares Of Beneficial Interest [Member] Document Type Document Type Class of Stock [Axis] Class of Stock [Axis] Pre-commencement Tender Offer Pre-commencement Tender Offer Entity Central Index Key Entity Central Index Key Entity Emerging Growth Company Entity Emerging Growth Company