Favorable and Unfavorable Acquired Lease Contracts, net - Future Amortization (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Expected future amortization of lease contract rights
2018	$ 5.3
2019	5.2
2020	5.2
2021	5.2
2022	5.1
2023 and Thereafter	28.1
Acquired Intangible Assets, Net	54.1	$ 61.3
Expected future (accretion) of lease contract rights
2018	(6.7)
2019	(5.6)
2020	(3.7)
2021	(2.8)
2022	(2.6)
2023 and Thereafter	(10.1)
Total acquired fair value of lease contracts, net	(31.5)	(40.2)
Expected future amortization (accretion) of lease contract rights
2018	2.7
2019	2.0
2020	0.7
2021	0.5
2022	1.0
2023 and Thereafter	1.3
Total	(8.2)
Favorable
Expected future amortization of lease contract rights
2018	4.0
2019	3.6
2020	3.0
2021	2.3
2022	1.6
2023 and Thereafter	8.8
Acquired Intangible Assets, Net	$ 23.3	$ 30.0