Debt (Tables)

6 Months Ended

Jun. 30, 2020

Long-term Debt, Unclassified [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

Long-term debt as of June 30, 2020 and December 31, 2019 consists of the following (in thousands):

	June 30, 2020		December 31, 2019
6.0% Senior Notes	$	650,000	$	650,000
Convertible Notes:
3.25% Convertible Notes	402,414		402,500
1.75% Convertible Notes	550,000		550,000
Total Notes	1,602,414		1,602,500
Less: Unamortized discount	127,381		139,981
Deferred issuance costs	12,577		14,058
Total long-term debt	1,462,456		1,448,461
Less: current portion	391,092		385,532
Total long-term debt, less current portion	$	1,071,364	$	1,062,929