Fair Value Measurements and Disclosures Notes Receivable (Details) - USD ($) $ in Millions	Mar. 31, 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	$ 162.0	$ 188.6
Senior Notes fair value	81.00%	94.30%
5.75% Senior Notes due 2026 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Payable, Fair Value Disclosure	$ 307.8	$ 599.4
Senior Notes fair value	51.30%	99.90%
6.125% Senior Notes due 2024 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Payable, Fair Value Disclosure	$ 225.6	$ 409.2
Senior Notes fair value	56.40%	102.30%
6.25% Senior Notes due 2025 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Payable, Fair Value Disclosure	$ 52.5	$ 0.0
Senior Notes fair value	51.30%	0.00%