Summary of Significant Accounting Policies - Reconciliation of shares used to determine net income per share (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Summary of Significant Accounting Policies
Net income	$ 15,531	$ 29,555
Weighted average number of shares - basic	45,298,514	44,779,822
Shares underlying options	2,012,513	1,956,649
Weighted average number of shares outstanding - diluted	47,311,027	46,736,471