Stock-Based Compensation - Restricted stock unit activity (Details) - Restricted Stock Units $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Shares
Outstanding, beginning balance (in shares) | shares	808,424
Granted (in shares) | shares	38,988
Vested (in shares) | shares	(64,912)
Cancelled (in shares) | shares	(17,672)
Outstanding, ending balance (in shares) | shares	764,828
Weighted- Average Grant- Date Fair Value
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 27.94
Granted (in dollars per share) | $ / shares	25.39
Vested (in dollars per share) | $ / shares	27.83
Cancelled (in dollars per share) | $ / shares	26.44
Outstanding, ending balance (in dollars per share) | $ / shares	$ 27.85
Weighted-Average Remaining Contractual Term (Years), Outstanding	4 years
Aggregate Intrinsic Value, Vested | $	$ 1,870
Aggregate Intrinsic Value, Outstanding | $	$ 14,004