Description of the business and recent developments: Basic and diluted net income per common share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Diluted weighted average shares
Weighted average common shares - basic (in shares)	46,229,603	45,754,880	46,227,528	45,760,302
Weighted average common shares - diluted	46,229,603	46,686,665	46,744,070	46,592,445
Stock options
Diluted weighted average shares
Dilutive effect (options or restricted stock)		205,823	33,084	128,477
Anti-dilutive effects
Anti-dilutive (options or restricted stock)	36,063	18,496	56,022	13,172
Restricted stock
Diluted weighted average shares
Dilutive effect (options or restricted stock)		725,962	483,458	703,666
Anti-dilutive effects
Unvested shares of restricted common stock	1,420,759	1,521,942	1,420,759	1,521,942
Anti-dilutive (options or restricted stock)	28,019		181,265