Fair Value Measurements - Additional Information (Details)	Jun. 30, 2018 USD ($) instruments properties portfolio
Fair value of other financial instruments
Number of portfolios comprised of properties held for sale | portfolio	1
Number of properties, held for sale | properties	17
Fair value, measurements, nonrecurring
Fair value of other financial instruments
Assets subject to impairment fair value disclosure | $	$ 0
Cash Flow Hedging | Interest Rate Swap
Fair value of other financial instruments
Outstanding interest rate swap contracts designated as cash flow hedges | instruments	5,000