Stock-based compensation - Schedule of Service Vesting-Based Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Wtd. Avg. Exercise Price
Outstanding as of end of period (in dollars per share)	$ 2.22
Service vesting-based stock options
Shares
Outstanding as of beginning of period (in shares)	127,000	217,250	456,293
Exercised (in shares)	(10,000)	(90,250)	(239,043)
Outstanding at end of year (in shares)	117,000	127,000	217,250
Stock options exercisable at year end (in shares)	117,000	127,000	217,250
Wtd. Avg. Exercise Price
Outstanding as of beginning of period (in dollars per share)	$ 2.19	$ 2.21	$ 2.17
Exercised (in dollars per share)	1.83	2.23	2.12
Outstanding as of end of period (in dollars per share)	2.22	2.19	2.21
Stock options exercisable at year end (in dollars per share)	$ 2.22	$ 2.19	$ 2.21