Bradley Agreement - Schedule of Interest and Premium Received and Deficiency Payments (Details) - Bradley International Airport parking facilities operating agreement - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Loss Contingencies [Line Items]
Deficiency repayments	$ 0.6	$ 0.1
Interest	0.0	0.0
Premium	$ 0.1	$ 0.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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