Bradley Agreement (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deficiency payments:
Balance at the beginning of the year	$ 14,649	$ 14,598
Deficiency payments made	25	924
Deficiency payments received	(1,347)	(873)
Balance at the end of the year	13,327	14,649	14,598
Compensation
Management fees	0	0	0
Bradley International Airport parking facilities operating agreement
Agreement
Agreement period with the State of Connecticut for operation of parking spaces	25 years
Number of garage parking spaces at Bradley International Airport operated	3,500
Annual minimum guaranteed payment to the State by the trustee	10,815	10,593
Deficiency payments:
Maximum premium percentage on initial deficiency payment	10.00%
Net deficiency payments received (paid)	1,322	51
Interest income on deficiency payment received from trustee	513	477
Premium income on deficiency payment received from trustee	140	69
Estimated accrued deficiency payments	0	100
Compensation
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	14,733	13,733
Bradley International Airport parking facilities operating agreement | Minimum
Agreement
Annual minimum guaranteed payment to the State by the trustee	8,300
Bradley International Airport parking facilities operating agreement | Maximum
Agreement
Annual minimum guaranteed payment to the State by the trustee	13,200
Bradley International Airport parking facilities operating agreement | State of Connecticut special facility revenue bonds | Minimum
Agreement
Annual principal and interest on revenue bonds	3,600
Bradley International Airport parking facilities operating agreement | State of Connecticut special facility revenue bonds | Maximum
Agreement
Annual principal and interest on revenue bonds	$ 4,500