Transactions With Parkway Properties, Inc. (Discontinued Operations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations	$ 19,163	$ 31,848	$ 20,764
Gain (loss) on sale of discontinued operations, net	0	(551)	19,358
Spin-off
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Rental property revenues	136,927	176,828	182,714
Rental property operating expenses	(58,336)	(73,630)	(80,099)
Other revenues	288	450	4,064
Interest expense	(6,022)	(7,988)	(8,127)
Depreciation and amortization	(47,345)	(63,791)	(77,760)
Other expenses	(6,349)	(21)	(28)
Income from discontinued operations	19,163	31,848	20,764
Gain (loss) on sale of discontinued operations, net	0	(551)	19,358
Cash provided by operating activities	42,604	76,395	81,946
Cash used in investing activities	$ (30,067)	$ (55,085)	$ 6,001