Other Financial Statement Disclosures Accrued liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Pension and other postretirement benefits	$ 17,897	$ 26,219
Compensation and related employee costs	66,144	88,186
Interest	35,578	47,414
Income taxes	16,514	13,265
Other	15,358	19,175
Total accrued liabilities	$ 151,491	$ 194,259