CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 99,857	$ 24,012	$ (156,967)
Other comprehensive income (loss), net of tax:
Unrealized gain on derivative instruments and other assets	612	7,407	4,918
Foreign currency translation adjustments	48,917	(22,270)	(43,718)
Equity in unrealized loss of an investee	0	(22)	(132)
Total comprehensive income (loss)	149,386	9,127	(195,899)
Less: comprehensive income attributable to noncontrolling interest in consolidated subsidiary	0	0	(20,057)
Comprehensive income (loss) attributable to Equity Commonwealth	$ 149,386	$ 9,127	$ (215,956)