CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common shares and paid-in surplus	Retained earnings	AOCI, after tax	Total	Non-controlling interest	Total Equity	Foreign Currency Gain (Loss) AOCI, after tax	Foreign Currency Gain (Loss) Total	Foreign Currency Gain (Loss) Non-controlling interest	Foreign Currency Gain (Loss) Total Equity	BAM Non-controlling interest	BAM Total Equity	MediaAlpha Non-controlling interest	MediaAlpha Total Equity
Beginning Balances at Dec. 31, 2017		$ 670.6	$ 2,823.2	$ (1.3)	$ 3,492.5	$ (131.7)	$ 3,360.8
Increase (Decrease) in Shareholders' Equity
Net income (loss)	$ (50.9)		(3.7)		(3.7)	(47.2)	(50.9)
Net change in foreign currency translation and other				(1.5)				$ (1.5)	$ (1.5)	$ 0.0	$ (1.5)
Total comprehensive income (loss)	(5.4)		(3.7)		(5.2)	(47.2)	(52.4)
Dividends declared on common shares			(3.8)		(3.8)		(3.8)
Dividends to non-controlling interests						(6.0)	(6.0)
Repurchases and retirements of common shares		$ (104.6)	(408.4)		(513.0)		(513.0)
Issuance of common shares (shares)		2.0
Issuance of common shares					2.0		2.0
Capital contributions from BAM members, net of tax												$ 22.9	$ 22.9
Amortization of restricted share awards		$ 9.7			9.7		9.7
Recognition of equity-based units of subsidiary		4.5			4.5	2.3	6.8
Dilution from equity-based units of subsidiary		(1.1)			(1.1)	1.1	0.0
Acquisition of subsidiary		(1.6)			(1.6)		(1.6)
Acquisition of non-controlling interests						14.2	14.2
Ending Balances at Sep. 30, 2018		579.5	2,407.3	(2.8)	2,984.0	(144.4)	2,839.6
Beginning Balances at Jun. 30, 2018		$ 575.8	2,366.5	(2.2)	2,940.1	(142.6)	2,797.5
Increase (Decrease) in Shareholders' Equity
Net income (loss)	30.6		40.8		40.8	(10.2)	30.6
Net change in foreign currency translation and other				(0.6)				(0.6)	(0.6)	0.0	(0.6)
Total comprehensive income (loss)	40.0		40.8		$ 40.2	(10.2)	30.0
Dividends to non-controlling interests						$ (1.9)	$ (1.9)
Issuance of common shares (shares)		0.2			0.2	0.0	0.2
Capital contributions from BAM members, net of tax												10.3	10.3
Amortization of restricted share awards		$ 3.3			$ 3.3		$ 3.3
Recognition of equity-based units of subsidiary		0.2			0.2	$ 0.0	0.2
Ending Balances at Sep. 30, 2018		579.5	2,407.3	(2.8)	2,984.0	(144.4)	2,839.6
Beginning Balances at Dec. 31, 2018	2,718.2	584.0	2,264.9	(5.8)	2,843.1	(124.9)	2,718.2
Increase (Decrease) in Shareholders' Equity
Net income (loss)	331.3		353.6		353.6	(22.3)	331.3
Net change in foreign currency translation and other								(5.5)	(5.5)	(0.3)	(5.8)
Total comprehensive income (loss)	347.8		353.6	(5.5)	348.1	(22.6)	325.5
Dividends declared on common shares			(3.2)		(3.2)		(3.2)
Dividends to non-controlling interests						(1.6)	(1.6)
Repurchases and retirements of common shares		(1.1)	(3.8)		(4.9)		(4.9)
Issuance of common shares		2.2			2.2		2.2
Capital contributions from BAM members, net of tax												36.3	36.3
Net contributions from non-controlling interests						2.3	2.3
Amortization of restricted share awards		7.8			7.8		7.8
Recognition of equity-based units of subsidiary		0.3			0.3		0.3
Effect of deconsolidation of MediaAlpha														$ (13.8)	$ (13.8)
Acquisition of non-controlling interests						1.8	1.8
Ending Balances at Sep. 30, 2019	3,070.9	593.2	2,611.5	(11.3)	3,193.4	(122.5)	3,070.9
Beginning Balances at Jun. 30, 2019		590.5	2,562.8	(9.0)	3,144.3	(136.4)	3,007.9
Increase (Decrease) in Shareholders' Equity
Net income (loss)	43.2		48.7		48.7	(5.5)	43.2
Net change in foreign currency translation and other								$ (2.3)	$ (2.3)	$ (0.1)	$ (2.4)
Total comprehensive income (loss)	46.3		48.7	(2.3)	46.4	(5.6)	40.8
Dividends to non-controlling interests						(0.6)	(0.6)
Capital contributions from BAM members, net of tax												$ 19.3	$ 19.3
Net contributions from non-controlling interests						0.8	0.8
Amortization of restricted share awards		2.7			2.7		2.7
Ending Balances at Sep. 30, 2019	$ 3,070.9	$ 593.2	$ 2,611.5	$ (11.3)	$ 3,193.4	$ (122.5)	$ 3,070.9