Note 5 - Capital Stock (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Exercise or Vesting [Member]
Common Stock, Capital Shares Reserved for Future Issuance	2,000,000
Future Issuance [Member]
Common Stock, Capital Shares Reserved for Future Issuance	7,500,000
Preferred Stock, Shares Outstanding	0	0
Treasury Stock, Shares, Acquired	3,300,000
Treasury Stock, Value, Acquired, Cost Method	$ 262.3
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 451.0