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MAALP Capital (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017 | Dec. 31, 2016
Total Partnership Capital [Member] |  |  |  |
Increase (Decrease) in Partners' Capital [Roll Forward] |  |  |  |
Units Issued During Period, Value, Unit Options Exercised | $ 625 |  |  |
Limited Partner [Member] |  |  |  |
Capital Disclosure [Line Items] |  |  |  |
Noncontrolling Interest in Joint Ventures | 2,306 | $ 2,306 | $ 2,306 | $ 2,306
Increase (Decrease) in Partners' Capital [Roll Forward] |  |  |  |
Dividends, Preferred Stock, Cash | 922 | 922 |  |
Limited Partner [Member] | General Partners' Capital Account [Member] |  |  |  |
Increase (Decrease) in Partners' Capital [Roll Forward] |  |  |  |
Beginning Balance | 6,270,758 | 6,337,721 | 6,337,721 |
Net Income Allocated to General Partners | 48,097 | 40,983 |  |
Issuance of units | 105 | 68 |  |
Units repurchased and retired | (2,912) | (4,734) |  |
Units Issued During Period, Value, Unit Options Exercised | 625 |  |  |
General partner units issued in exchange for limited partner units | 2,780 | 167 |  |
Units issued in exchange for redeemable units | 1,915 | 1,482 |  |
Redeemable stock fair market value | 965 | (298) |  |
Adjustment for noncontrolling interest ownership in operating partnership | 63 | 192 |  |
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | (233) |  |  |
Amortization of unearned compensation | 4,024 | 3,025 |  |
Distributions | (104,971) | (98,841) |  |
Ending Balance | 6,221,216 | 6,279,765 | 6,270,758 | 6,337,721
Limited Partner [Member] | Total Partnership Capital [Member] |  |  |  |
Increase (Decrease) in Partners' Capital [Roll Forward] |  |  |  |
Beginning Balance | 6,573,875 | 6,642,082 | 6,642,082 |
Net Income Available for Common Unitholders | 50,820 | 43,416 |  |
Other comprehensive (loss) income - derivatives insturments (cash flow hedges) | 639 | 3,192 |  |
Issuance of units | 105 | 2,075 |  |
Units repurchased and retired | (2,912) | (4,734) |  |
General partner units issued in exchange for limited partner units | 0 | 0 |  |
Units issued in exchange for redeemable units | 1,915 | 1,482 |  |
Redeemable stock fair market value | 965 | (298) |  |
Adjustment for noncontrolling interest ownership in operating partnership | 0 | 0 |  |
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | 0 |  |  |
Amortization of unearned compensation | 4,024 | 3,025 |  |
Distributions | (108,790) | (102,505) |  |
Dividends, Preferred Stock, Cash | 922 | 922 |  |
Ending Balance | 6,520,344 | 6,586,813 | 6,573,875 | 6,642,082
Limited Partner [Member] | Limited Partner [Member] |  |  |  |
Increase (Decrease) in Partners' Capital [Roll Forward] |  |  |  |
Beginning Balance | 231,676 | 235,976 | 235,976 |
Net Income Allocated to Limited Partners | 1,801 | 1,511 |  |
General partner units issued in exchange for limited partner units | (2,780) | (167) |  |
Adjustment for noncontrolling interest ownership in operating partnership | (63) | (192) |  |
Distributions | (3,819) | (3,664) |  |
Ending Balance | 226,815 | 233,464 | 231,676 | 235,976
Limited Partner [Member] | AOCI Attributable to Noncontrolling Interest [Member] |  |  |  |
Increase (Decrease) in Partners' Capital [Roll Forward] |  |  |  |
Beginning Balance | 2,295 | 1,246 | 1,246 |
Other comprehensive (loss) income - derivatives insturments (cash flow hedges) | 639 | 3,192 |  |
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | 233 |  |  |
Ending Balance | 3,167 | 4,438 | 2,295 | 1,246
Accumulated Distributions in Excess of Net Income [Member] | Limited Partner [Member] |  |  |  |
Increase (Decrease) in Partners' Capital [Roll Forward] |  |  |  |
Issuance of units | 0 | 2,007 | $ 66,840 | $ 64,833
Dividends, Preferred Stock, Cash | 922 | 922 |  |
Preferred Stock Including Additional Paid in Capital [Member] | Limited Partner [Member] |  |  |  |
Increase (Decrease) in Partners' Capital [Roll Forward] |  |  |  |
Ending Balance | $ 66,840 | $ 66,840 |  |

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