Bradley Agreement (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2000	Mar. 31, 2015 item	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Deficiency payments:
Interest income on deficiency payment received from trustee		$ 43
Deficiency payments
Deficiency payments:
Balance at the beginning of the year		13,327		13,327
Deficiency payments made		38
Deficiency payments received		(43)
Balance at the end of the year		13,322
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				11,042	10,815
Deficiency payments:
Maximum premium percentage on initial deficiency payment		10.00%
Net deficiency payments received (paid)		5	92
Premium income on deficiency payment received from trustee		8
Estimated accrued deficiency payments		0	14		0
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		14,983			14,733
Management Fees		0	0
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