Stock Repurchases (Details) - Class A Common Shares - USD ($) $ in Millions	209 Months Ended
	Jan. 31, 2020	Aug. 19, 2002
Equity, Class of Treasury Stock [Line Items]
Common stock shares repurchased (in shares)	4,588,632
Cost of common stock repurchased	$ 25.6
Shares Stock Repurchase Plan, August 19, 2002
Equity, Class of Treasury Stock [Line Items]
Approved number of shares to be repurchased		2,000,000
Common stock shares repurchased (in shares)	1,053,679
Cost of common stock repurchased	$ 6.2