Note 2 - Summary of Significant Accounting Policies Level 4 Text (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 segment banks	Dec. 31, 2013	Dec. 31, 2012	Oct. 28, 2014	Apr. 07, 2014
maturityofcashandcashequiv	3 months
number of banks that contain most of our cash	2
Inventory Valuation Reserves	$ 27.0	$ 22.6
Minimum Aircraft Estimated Useful Life	16 years 6 months
Maximum Aircraft Estimated Useful Life	20 years
Minimum Estimated Useful Life of Other Equipment	3 years
Maximum Estimated Useful Life of Other Equipment	10 years
accumulated other comprehensive loss related to treasury lock	0.5	0.8
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	1.7	1.8
Fixed-Fee Rental Income	433.7	386.8	338.5
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2.5	3.3	4.1
Convertible Notes Payable - TPG	0	22.3
Convertible Notes Payable - EMB Fair Value		25.0
TPG - Stock Issued During Period, Shares, Conversion of Convertible Securities	2.2
EMB - Stock Issued During Period, Shares, Conversion of Convertible Securities	2.5
Stock Repurchase Program, Authorized Amount					75
Authorized amount available to repurchase common shares					50
Authorized amount to retire convertible notes					50
Repayment of TPG Convertible note					22.3
Convertible note payable - EMB redeemed				26.5
Convertible Notes Payable - EMB	$ 0	$ 24.5		$ 28.0
Number of Reportable Segments	1