Consolidated Statements of Cash Flows (Parenthetical)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
5 3/4% Senior Notes due 2019
Debt instrument interest rate	5.75%	5.75%	5.75%
7% Senior Notes due 2022
Debt instrument interest rate	7.00%	7.00%	7.00%
8 1/2% Senior Notes due 2020
Debt instrument interest rate	8.50%	8.50%	8.50%