Fair Value Measurements and Disclosures Notes Receivable (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
1.125% Convertible Senior Notes due 2021 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Payable, Fair Value Disclosure	$ 183.0	$ 188.6
Senior Notes fair value	91.50%	94.30%
5.75% Senior Notes due 2026 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Payable, Fair Value Disclosure	$ 547.2	$ 599.4
Senior Notes fair value	91.20%	99.90%
6.125% Senior Notes due 2024 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Payable, Fair Value Disclosure	$ 378.0	$ 409.2
Senior Notes fair value	94.50%	102.30%
6.25% Senior Notes due 2025 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Payable, Fair Value Disclosure	$ 86.3	$ 0.0
Senior Notes fair value	84.40%	0.00%