Partners' Capital of MAALP - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Scheduleof Capital Structure [Line Items]
Operating partnership units outstanding	118,313,567	117,955,568
General Partners' Capital Account, Units Outstanding	114,246,393	113,844,267
Limited Partners' Capital Account, Units Outstanding	4,067,174	4,111,301
Preferred Stock, Shares Outstanding	867,846	867,846
Redeemable Preferred Stock [Member]
Scheduleof Capital Structure [Line Items]
Preferred Stock, Shares Outstanding	867,846
Noncontrolling Interest [Member]
Scheduleof Capital Structure [Line Items]
Common Shares Issuable Upon Conversion Of Convertible Stock	4,067,174	4,111,301
Redeemable Capital Shares Par Or Stated Value Per Share	$ 131.86	$ 95.70
Limited Partners' Capital Account	$ 536.3	$ 393.5
M A A L P
Scheduleof Capital Structure [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	96.60%	96.50%