Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Summary of Changes in Accumulated Other Comprehensive Income

The following table summarizes the changes in accumulated other comprehensive income (loss) by component, net of tax, for the periods indicated: 

	Unrealized holding gains (losses) on AFS		Unrealized holding gains (losses) on SERP		Unrealized holding gains (losses) on junior subordinated debt		Impairment loss on securities		Total
	(in millions)
Balance, December 31, 2018	$	(47.5)	$	0.4	$	13.4	$	0.1	$	(33.6)
Other comprehensive income (loss) before reclassifications	71.2		(0.4)		(9.8)		—		61.0
Amounts reclassified from AOCI	(2.3)		—		—		(0.1)		(2.4)
Net current-period other comprehensive income (loss)	68.9		(0.4)		(9.8)		(0.1)		58.6
Balance, December 31, 2019	$	21.4	$	—	$	3.6	$	—	$	25.0
Other comprehensive income (loss) before reclassifications	70.9		(0.3)		(3.1)		—		67.5
Amounts reclassified from accumulated other comprehensive income	(0.2)		—		—		—		(0.2)
Net current-period other comprehensive income (loss)	70.7		(0.3)		(3.1)		—		67.3
Balance, December 31, 2020	$	92.1	$	(0.3)	$	0.5	$	—	$	92.3
Other comprehensive (loss) income before reclassifications	(69.0)		—		(1.2)		—		(70.2)
Amounts reclassified from AOCI	(6.4)		—		—		—		(6.4)
Net current-period other comprehensive (loss) income	(75.4)		—		(1.2)		—		(76.6)
Balance, December 31, 2021	$	16.7	$	(0.3)	$	(0.7)	$	—	$	15.7

Schedule of Reclassifications Out of Accumulated Other Comprehensive Income

The following table presents reclassifications out of accumulated other comprehensive income: 

	Year Ended December 31,
Income Statement Classification	2021		2020		2019
	(in millions)
Gain on sales of AFS debt securities, net	$	8.5	$	0.2	$	3.1
Income tax expense	(2.1)		—		(0.7)
Net of tax	$	6.4	$	0.2	$	2.4