Equity Incentive Plan (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2023	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Equity Incentive Plan
Maximum number of common shares available for issuance (in shares)		6,828,527
Restricted share awards
Summary of non-vested shares/units
Unvested at the beginning of the period (in shares)		2,267,870
Granted (in shares)		640,407
Vested (in shares)		(378,807)
Forfeited (in shares)		(1,554)
Unvested at the end of the period (in shares)		2,527,916
Weighted Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share)		$ 15.32
Granted (in dollars per share)		11.33
Vested (in dollars per share)		15.10
Forfeited (in dollars per share)		13.55
Unvested at the end of the period (in dollars per share)		$ 14.34
Other Disclosures
Share-based compensation expense		$ 3.6	$ 3.5
Total unrecognized compensation costs		$ 23.0
Weighted-average period of recognition of unrecognized share-based compensation expense		1 year 9 months 18 days
Total fair value of shares vested		$ 4.4	3.4
2015 Share Repurchase Program [Member]
Other Disclosures
Performance-based vesting period		3 years
Time-based vesting period		1 year
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period		4 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Contingent on Absolute Total Shareholder Return		40.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Contingent on Relative Total Shareholder Return		60.00%
Vesting percentage upon satisfaction of performance-based vesting period		50.00%
Vesting percentage upon satisfaction of time-based vesting period		50.00%
Percentage of grant date fair value to be recognized over three years		50.00%
Employee service share based compensation cost period of recognition		3 years
Percentage of grant date fair value to be recognized over four years		50.00%
Employee service share based compensation cost period of recognition		4 years
Performance Units
Other Disclosures
Share-based compensation expense		$ 2.1	$ 1.7
Total unrecognized compensation costs		$ 18.0
Weighted-average period of recognition of unrecognized share-based compensation expense		2 years 2 months 12 days
Performance-based vesting period		4 years
2020 Performance Shares [Member]
Summary of non-vested shares/units
Granted (in shares)	200,000				489,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share					$ 11.59
Other Disclosures
Fair value assumptions, risk free interest rate					1.08%
Fair value assumptions, expected volatility rate					23.46%
2021 Performance Shares
Summary of non-vested shares/units
Granted (in shares)				431,151
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share				$ 20.90
Other Disclosures
Share-Based Compensation Arrangement by Share-Based Payment Award, Contingent on Absolute Total Shareholder Return		2500.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Contingent on Relative Total Shareholder Return		75.00%
Fair value assumptions, risk free interest rate				0.23%
Fair value assumptions, expected volatility rate				69.47%
Percentage of grant date fair value to be recognized over three years		100.00%
Employee service share based compensation cost period of recognition		3 years
2022 Performance Shares
Summary of non-vested shares/units
Granted (in shares)			407,024
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share			$ 21.96
Other Disclosures
Fair value assumptions, risk free interest rate			1.70%
Fair value assumptions, expected volatility rate			70.15%
2021 Share Repurchase Program
Other Disclosures
Common shares available for future grant (in shares)		2,770,454
2023 Performance Shares
Summary of non-vested shares/units
Granted (in shares)		574,846
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share		$ 16.90
Other Disclosures
Fair value assumptions, risk free interest rate		4.33%
Fair value assumptions, expected volatility rate		66.70%
Minimum | 2015 Share Repurchase Program [Member]
Other Disclosures
Percentage of performance units that will convert into restricted shares		0.00%
Minimum | 2020 Performance Shares [Member]
Equity Incentive Plan
Shared-Based Compensation Arrangement by Share-Based Payment Award, Conversion Percentage Range				0.00%
Minimum | 2021 Performance Shares
Equity Incentive Plan
Shared-Based Compensation Arrangement by Share-Based Payment Award, Conversion Percentage Range			0.00%
Minimum | 2022 Performance Shares
Equity Incentive Plan
Shared-Based Compensation Arrangement by Share-Based Payment Award, Conversion Percentage Range		0.00%
Minimum | 2023 Performance Shares
Equity Incentive Plan
Shared-Based Compensation Arrangement by Share-Based Payment Award, Conversion Percentage Range		0.00%
Maximum | 2015 Share Repurchase Program [Member]
Other Disclosures
Percentage of performance units that will convert into restricted shares		200.00%
Maximum | 2020 Performance Shares [Member]
Equity Incentive Plan
Shared-Based Compensation Arrangement by Share-Based Payment Award, Conversion Percentage Range				200.00%
Maximum | 2021 Performance Shares
Equity Incentive Plan
Shared-Based Compensation Arrangement by Share-Based Payment Award, Conversion Percentage Range			200.00%
Maximum | 2022 Performance Shares
Equity Incentive Plan
Shared-Based Compensation Arrangement by Share-Based Payment Award, Conversion Percentage Range		200.00%
Maximum | 2023 Performance Shares
Equity Incentive Plan
Shared-Based Compensation Arrangement by Share-Based Payment Award, Conversion Percentage Range		200.00%