Description of the business and recent developments: Basic and diluted net income per common share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Diluted weighted average shares
Weighted average common shares - basic (in shares)	46,293,524	45,815,718	46,290,452	45,818,677
Weighted average common shares - diluted	46,866,929	45,815,718	46,825,948	46,598,870
Stock options
Diluted weighted average shares
Dilutive effect (options or restricted stock)	36,406		34,191	99,581
Anti-dilutive effects
Anti-dilutive (options or restricted stock)	43,648	87,214	42,531	24,453
Restricted stock
Diluted weighted average shares
Dilutive effect (options or restricted stock)	536,999		501,305	680,612
Anti-dilutive effects
Unvested shares of restricted common stock	1,371,217	1,472,572	1,371,217	1,472,572
Anti-dilutive (options or restricted stock)	827	925,866	133,468	191