XML 31 R13.htm IDEA: XBRL DOCUMENT

Acquisition	3 Months Ended
Acquisition	Mar. 31, 2018
Business Combinations [Abstract]
Acquisition	Acquisition On February 9, 2018, we acquired 537 West 26th Street, a 14,000 square foot commercial property adjacent to our 260 Eleventh Avenue office property and 55,000 square feet of additional zoning air rights, for $44,000,000.