Stock Compensation Plans and Share-Based Compensation Awards - RSU (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stock Compensation Plans and Share-Based Compensation Awards
Share-based compensation expense	$ 3,585	$ 1,845
RSUs
Stock Compensation Plans and Share-Based Compensation Awards
Share-based compensation expense	1,700	700
Unrecognized compensation expense	$ 27,700	$ 18,300
Vesting period	4 years
Weighted average period outstanding for unvested RSUs	3 years	3 years 4 months 24 days
Total fair value of share based awards vested	$ 3,200	$ 0
Number outstanding
Balance at beginning of period (in shares)	876
Granted (in shares)	601
Vested (in shares)	(124)
Forfeited (in shares)	(8)
Balance at end of period (in shares)	1,345
Weighted average grant date fair value
Balance at beginning of period (in dollars per share)	$ 22.30
Granted (in dollars per share)	23.22
Vested (in dollars per share)	26.01
Forfeited (in dollars per share)	22.41
Balance at end of period (in dollars per share)	$ 22.37