Earnings Per Share - Anti-Dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of anti-dilutive securities excluded from diluted earnings per share (in shares)	2,241,223	547,652
Restricted share awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of anti-dilutive securities excluded from diluted earnings per share (in shares)	2,241,223	482,152
Share options / BSPCE
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of anti-dilutive securities excluded from diluted earnings per share (in shares)	0	65,500