Description of the business and recent developments: Basic and diluted net income per common share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Diluted weighted average shares
Weighted average common shares - basic (in shares)	46,419,180	45,947,772	45,542,315
Weighted average common shares - diluted	46,963,920	46,668,198	46,080,395
Stock options
Diluted weighted average shares
Dilutive effect (options or restricted stock)	34,007	80,849	32,222
Anti-dilutive effects
Anti-dilutive (options or restricted stock)	45,809	32,324	39,608
Restricted stock
Diluted weighted average shares
Dilutive effect (options or restricted stock)	510,733	639,577	505,858
Anti-dilutive effects
Unvested shares of restricted common stock	1,253,321	1,339,596	1,283,281
Anti-dilutive (options or restricted stock)	86,619	223,118	348