Subsequent Events subsequent Events (Details)	Feb. 03, 2017 USD ($) shares	Jan. 25, 2017 USD ($) yr indices tiers	Dec. 31, 2016 shares	May 17, 2016 shares	Dec. 31, 2015 shares	May 20, 2014 shares
Subsequent Event [Line Items]
Common stock, shares issued | shares			153,869,075	1,507	153,658,866	7,542
MYLTIPS 2017 | NAREIT Office Index adjusted [Member]
Subsequent Event [Line Items]
Weighted Percentage of Index Used to Compare to TSR		50.00%
MYLTIP vesting 2021 | MYLTIPS 2017
Subsequent Event [Line Items]
Vesting Percentage		50.00%
Subsequent Event [Member]
Subsequent Event [Line Items]
LTIP units issued (in shares) | shares	100,639
Subsequent Event [Member] | MYLTIPS 2017
Subsequent Event [Line Items]
Threshold Tier		$ 10,700,000
Target Tier		21,300,000
High Tier		32,000,000
Exceptional Tier		$ 42,700,000
Indices Used to Compare TSR | indices		2
Number of Tiers | tiers		4
Percentage of annualized TSR for Reduction of Earned Awards		0.00%
Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards		12.00%
Distributions percent before measurement date		10.00%
Value of MYLTIP Awards		$ 17,700,000
MYLTIP Value Amortized Into Earnings, Years | yr		4
TSR measurement (in years) | yr		3
Subsequent Event [Member] | MYLTIPS 2017 | Cohen & Steers Realty Majors Portfolio Index [Member]
Subsequent Event [Line Items]
Weighted Percentage of Index Used to Compare to TSR		50.00%
Subsequent Event [Member] | MYLTIP 2014
Subsequent Event [Line Items]
Final awards percentage of target	27.70%
Value of MYLTIP Awards	$ 3,500,000
MYLTIP Units forfeited | shares	447,386
Subsequent Event [Member] | Minimum [Member] | MYLTIPS 2017
Subsequent Event [Line Items]
Potential Awards Earned		$ 0
Subsequent Event [Member] | Maximum [Member] | MYLTIPS 2017
Subsequent Event [Line Items]
Potential Awards Earned		$ 42,700,000
Subsequent Event [Member] | MYLTIP vesting 2020 | MYLTIPS 2017
Subsequent Event [Line Items]
Vesting Percentage		50.00%
Subsequent Event [Member] | Restricted Stock [Member]
Subsequent Event [Line Items]
Common stock, shares issued | shares	35,839