Employee Benefits (Details Textual) $ / shares in Units, $ in Millions		12 Months Ended
	Apr. 26, 2019 shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 CAD ($)	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Dec. 31, 2019 CAD ($) shares	Dec. 31, 2019 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Amount of shares purchased in the open market | $		$ 2,414,000		$ 4,000,000	$ 0
Dividends payable | $				7,710,000			$ 7,362,000
Accrued dividends | $				1,576,000			1,303,000
Accrued liability | $				600,000			$ 100,000
Litigation Settlement, Expense		$ 0	$ 5	$ 0	$ 4,009,000
Deferred Compensation Share Based Payments | Share-based Compensation Award, Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of deferred share units vesting			50.00%	50.00%	20.00%
Deferred Compensation Share Based Payments | Share-based Compensation Award, Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of deferred share units vesting			25.00%	25.00%	40.00%
Deferred Compensation Share Based Payments | Share-based Compensation Award, Tranche Three
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of deferred share units vesting			25.00%	25.00%	60.00%
Deferred Compensation Share Based Payments | Share Based Compensation Award Tranche Four
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of deferred share units vesting					80.00%
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total number of shares that may be issued under the stock based compensation Plan (including predecessor plans to the Plan)						5,048,100	5,048,100
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	200,000
Shares remain available for issuance						527,000	527,000
Vested, shares		162,287
Remaining unrecognized compensation cost | $							$ 13,400,000
Remaining unrecognized compensation cost recognized over a remaining weighted average period		2 years 1 month 6 days
Number of vested shares from employees on the date vesting		62,036
Nonvested restricted shares (in shares)				440,073		396,598	396,598
Restricted Stock | Employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares granted to employees vesting period		4 years
Restricted Stock | Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares granted to employees vesting period		1 year
Canadian Plan | Westwood International Advisors Inc
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares remain available for issuance						59,000	59,000
Fund purchases of common stock						$ 10	$ 7,700,000
Purchases of common stock with respect to awards granted | $		$ 1,700,000
Share price | $ / shares							$ 29.62
Number of shares purchased in the open market		25,047
Vested, shares		24,840
Fair value of vested shares | $		$ 800,000
Treasury Stock, Common, Shares						36,238	36,238
Purchase of treasury stock, shares		1,000,000.0
Remaining unrecognized compensation cost | $							$ 700,000
Remaining unrecognized compensation cost recognized over a remaining weighted average period		1 year 8 months 12 days
Compensation expense recorded | $		$ 200,000		$ 100,000	$ 200,000
Deferred Compensation Share Based Payments
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares granted to employees vesting period			6 years	6 years
Accrued liability | $							$ 500,000
Deferred share units, issued and outstanding		17,401
Mutual Fund [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Mutual fund vesting period		2 years
Service period of mutual fund share incentive award		3 years
Compensation expense recorded | $				$ 300,000	$ 1,200,000
Benefit Plans [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
Percentage of compensation		6.00%