Credit Risk and Fair Value of Financial Instruments Level 3 (Tables)

12 Months Ended

Dec. 31, 2017

Credit Risk and Fair Value of Financial Instruments [Abstract]

Fair Value, Measurement Inputs, Disclosure [Table Text Block]

The fair value of our debt instruments at December 31 was as follows:

	2017		2016
	(In thousands)
7.625% Senior Notes due October 2018	$	259,563	$	272,353
4.5% Senior Notes due November 2020	199,590		205,000
8.0% Senior Notes due November 2021	175,313		175,500
5.375% Senior Notes due January 2022	436,178		444,614
5.375% Senior Notes due May 2024	892,118		884,000
4.625% Senior Notes due December 2027	558,250		—
7.5% Senior Notes due April 2027	238,004		231,590
Term Loan due March 2021	—		673,750
Bank Credit Facility due March 2021	—		350,000
Term Loan due December 2022	675,000		—
Mortgage notes and other debt, maturities through 2050	6,036		3,753
Total fair value of debt instruments	$	3,440,052	$	3,240,560