Quarterly report pursuant to Section 13 or 15(d)

Fair Value Disclosures (Details Textual)

v3.2.0.727
Fair Value Disclosures (Details Textual) - Senior Notes [Member]
Jun. 30, 2015
Jun. 02, 2015
Dec. 31, 2014
4.50% senior notes due 2018 [Member]      
Fair Value Disclosures (Textual) [Abstract]      
Debt instrument, stated rate (percent) 4.50%   4.50%
7.15% senior notes due 2020 [Member]      
Fair Value Disclosures (Textual) [Abstract]      
Debt instrument, stated rate (percent) 7.15%   7.15%
7.00% senior notes due 2022 [Member]      
Fair Value Disclosures (Textual) [Abstract]      
Debt instrument, stated rate (percent) 7.00%   7.00%
6.00% senior notes due 2025 [Member]      
Fair Value Disclosures (Textual) [Abstract]      
Debt instrument, stated rate (percent) 6.00% 6.00%  
1.875% convertible senior notes due 2032 [Member]      
Fair Value Disclosures (Textual) [Abstract]      
Debt instrument, stated rate (percent) 1.875%   1.875%