Income taxes: Components of income before income taxes (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Components of income before income taxes
Domestic	$ 14,113,000	$ 16,332,000	$ 31,902,000	$ 35,084,000
Foreign	(2,814,000)	(6,152,000)	(7,770,000)	(12,136,000)
Income before income taxes	$ 11,299,000	$ 10,180,000	$ 24,132,000	$ 22,948,000

The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

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