Note 6 - Fair Value Measurements (Details) - Estimated Fair Value of Senior Notes (Parentheticals)	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
5.375% Senior Notes Due December 2014 [Member]
Note 6 - Fair Value Measurements (Details) - Estimated Fair Value of Senior Notes (Parentheticals) [Line Items]
Senior Notes, maturity date	2014	2014
Senior Notes, interest rate	5.375%	5.375%
5.375% Senior Notes Due July 2015 [Member]
Note 6 - Fair Value Measurements (Details) - Estimated Fair Value of Senior Notes (Parentheticals) [Line Items]
Senior Notes, maturity date	2015	2015
Senior Notes, interest rate	5.375%	5.375%
5.625% Senior Notes Due 2020 [Member]
Note 6 - Fair Value Measurements (Details) - Estimated Fair Value of Senior Notes (Parentheticals) [Line Items]
Senior Notes, maturity date	2020	2020
Senior Notes, interest rate	5.625%	5.625%
5.5% Senior Notes Due 2024 [Member]
Note 6 - Fair Value Measurements (Details) - Estimated Fair Value of Senior Notes (Parentheticals) [Line Items]
Senior Notes, maturity date	2024	2024
Senior Notes, interest rate	5.50%	5.50%
6.000% Senior Notes Due January 2043 [Member]
Note 6 - Fair Value Measurements (Details) - Estimated Fair Value of Senior Notes (Parentheticals) [Line Items]
Senior Notes, maturity date	2043	2043
Senior Notes, interest rate	6.00%	6.00%