Derivatives Fair Value of Convertible Debt Hedges (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Values Convertible Debt Hedges, Net	$ 0
Fair Values Convertible Debt Hedges, Gain (Loss)	0	$ (273,000)
Fair Value, Inputs, Level 2 | Convertible Debt Conversion Feature | Fair Value, Measurements, Recurring
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Convertible 2021 debt conversion liability	0
Fair Value, Inputs, Level 2 | Convertible Debt 2022 Conversion Feature | Fair Value, Measurements, Recurring
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Convertible Debt Conversion Feature	0
Fair Value, Inputs, Level 2 | Convertible Debt Bond Hedge | Fair Value, Measurements, Recurring
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Convertible 2021 note hedge asset	0
Convertible 2022 note hedge asset	0
Convertible Subordinated Debt | Convertible Senior Notes at 4.50% February 2022 [Domain]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Convertible Debt Conversion Feature Gain (Loss)	0	(8,684,000)
Convertible Debt Note Hedge Gain (Loss)	0	8,622,000
Convertible Subordinated Debt | Convertible Senior Notes at 5.00% February 2021 [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Convertible Debt Conversion Feature Gain (Loss)	0	(6,715,000)
Convertible Debt Note Hedge Gain (Loss)	$ 0	$ 6,504,000