Description of the business: Stockholders' deficit (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Increase (Decrease) in Stockholders' Equity
Balance	$ (373,098)	$ (293,166)
Balance (in shares)	47,674,189
Equity-based compensation	$ 6,614	7,831
Foreign currency translation	(2,165)	(5,210)
Issuances of common stock		1
Exercises of options	204	215
Dividends paid	(41,298)	(36,081)
Net income	1,137	18,851
Balance	$ (408,606)	(307,559)
Balance (in shares)	47,926,580
Common Stock
Increase (Decrease) in Stockholders' Equity
Balance	$ 48	$ 47
Balance (in shares)	47,674,189	47,214,077
Forfeitures of shares granted to employees (in shares)	(9,582)	(19,676)
Issuances of common stock		$ 1
Issuances of common stock (in shares)	256,800	323,700
Exercises of options (in shares)	5,173	4,571
Balance	$ 48	$ 48
Balance (in shares)	47,926,580	47,522,672
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity
Balance	$ 547,734	$ 515,867
Equity-based compensation	6,614	7,831
Exercises of options	204	215
Balance	554,552	523,913
Accumulated Other Comprehensive Income
Increase (Decrease) in Stockholders' Equity
Balance	(11,003)	(1,306)
Foreign currency translation	(2,165)	(5,210)
Balance	(13,168)	(6,516)
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity
Balance	(909,877)	(807,774)
Dividends paid	(41,298)	(36,081)
Net income	1,137	18,851
Balance	$ (950,038)	$ (825,004)