Equity - Share Repurchase Program (Details) $ / shares in Units, $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2020 USD ($) shares	Aug. 31, 2020 USD ($) shares	Jun. 30, 2020 USD ($) shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) shares	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) shares	Mar. 25, 2020 USD ($) $ / shares shares
Stock Repurchase Program
Payments for Repurchase of Redeemable Preferred Stock | $					$ 6.4	$ 7.9
Gain (loss) attributable to preferred shares of a subsidiary company | $			$ 1.7	$ 1.7	$ (4.1)	$ (4.8)
Common Stock, Shares, Outstanding			91,952,348		91,952,348		108,675,294
Cumulative Preferred Stock
Stock Repurchase Program
Shares repurchased and canceled | $					$ 6.4
Series 1 Shares
Stock Repurchase Program
Shares repurchased and canceled (in shares)					381,794
Series 2 Shares
Stock Repurchase Program
Shares repurchased and canceled (in shares)					62,365
Series 3 Shares
Stock Repurchase Program
Shares repurchased and canceled (in shares)					120,000
NCIB
Stock Repurchase Program
Public float amount used to determine share amount, percent							10.00%
Shares repurchased and canceled (in shares)		2,729,780			4,810,325
Shares repurchased and canceled | $		$ 5.5			$ 10.3
Gain (loss) attributable to preferred shares of a subsidiary company | $					$ (7.4)
NCIB | Series 1 Shares
Stock Repurchase Program
Number of shares authorized for repurchase							384,750
Dividend percent of cumulative redeemable preferred shares					4.85
NCIB | Series 2 Shares
Stock Repurchase Program
Number of shares authorized for repurchase							223,072
Dividend percent of cumulative redeemable preferred shares					7.0
NCIB | Series 3 Shares
Stock Repurchase Program
Number of shares authorized for repurchase							133,031
SIB
Stock Repurchase Program
Number of shares authorized for repurchase								12,820,512
Shares repurchased and canceled (in shares)	12,500,000
Shares repurchased and canceled | $	$ 25.8
Share repurchase authorized amount | $								$ 25.0
Number of share repurchase authorized as percentage of common stock issued and outstanding								12.00%
Share purchase price increment | $ / shares								$ 0.05
Minimum | SIB
Stock Repurchase Program
Share purchase price | $ / shares								1.95
Maximum | NCIB
Stock Repurchase Program
Number of shares authorized for repurchase							10,578,799
Stock Repurchase Program Number Of Shares Authorized To Be Repurchased Per Day							9,243
Maximum | SIB
Stock Repurchase Program
Share purchase price | $ / shares								$ 2.20
Series E Debentures | NCIB
Stock Repurchase Program
Share repurchase authorized amount | $							$ 11.5