XML 67 R57.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Fair Value Measurements - Summary of Carrying Value and Estimated Fair Value of all Debt (Parenthetical) (Details)
Dec. 31, 2019
Jun. 30, 2019
Aug. 31, 2017
3.75% Convertible Notes      
Fair value measurement      
Interest rate (as a percent) 3.75% 3.75% 3.75%