Bradley Arrangement - Additional Information (Details)	6 Months Ended		12 Months Ended
	Jun. 30, 2016 USD ($) parking_space	Jun. 30, 2015 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2002 USD ($)	Dec. 31, 2025 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Management fees	$ 0
Bradley International Airport parking facilities operating agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Agreement period for operation of parking spaces	25 years
Number of garage parking spaces at Bradley International Airport operated | parking_space	3,500
Annual minimum guaranteed payment to the State by the trustee					$ 11,000,000
Maximum premium percentage on initial deficiency payment (not more than)	10.00%
Estimated accrued deficiency payments	$ 0				0
Management fee apportioned to the entity (as a percent)	60.00%
Management fee apportioned to an un-affiliated entity (as a percent)	40.00%
Unrecognized cumulative management fees	$ 16,200,000				$ 15,700,000
Management fees		$ 0
Minimum | Bradley International Airport parking facilities operating agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual minimum guaranteed payment to the State by the trustee						$ 8,300,000
State of Connecticut special facility revenue bonds | Minimum | Bradley International Airport parking facilities operating agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual principal and interest on revenue bonds						$ 3,600,000
Forecast | Bradley International Airport parking facilities operating agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual minimum guaranteed payment to the State by the trustee				$ 11,300,000
Forecast | Maximum | Bradley International Airport parking facilities operating agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual minimum guaranteed payment to the State by the trustee			$ 13,200,000
Forecast | State of Connecticut special facility revenue bonds | Maximum | Bradley International Airport parking facilities operating agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Annual principal and interest on revenue bonds							$ 4,500,000