Note 8 - Fair Value Measurements (Detail) - Carrying Amounts and Estimated Fair Value of Trading Investments (Senior Debt Obligations [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Estimate of Fair Value, Fair Value Disclosure [Member] | Line of Credit [Member]
Revolving lines of credit	$ 85.8
Estimate of Fair Value, Fair Value Disclosure [Member] | Loans Payable [Member]
Senior debt	200.0
Estimate of Fair Value, Fair Value Disclosure [Member] | Senior Notes [Member]
Senior debt	429.9
Line of Credit [Member]
Revolving lines of credit	85.8	99.8
Loans Payable [Member]
Senior debt	200.0	200.0
Senior Notes [Member]
Senior debt	$ 399.5	$ 449.4