Capital Stock - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized	200,000,000	200,000,000
Common stock, par value (in dollars per share)	$ 0.0002	$ 0.0002
Common stock, shares issued	30,424,391	29,988,460
Undesignated preferred stock, shares authorized	20,000,000	20,000,000
Undesignated stock par value (in dollars per share)	$ 0.00125	$ 0.00125
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares outstanding	30,424,391	29,988,460	29,696,682
Common shares reserved for future issuance	4,325,963
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock unit dividend equivalents	$ 433,000	$ 391,000	$ 450,000
Dividends payable	$ 623,000	$ 557,000	$ 434,000