Other Comprehensive Income/Loss (Tables)

6 Months Ended

9 Months Ended

Jun. 30, 2021

Sep. 30, 2021

Equity [Abstract]

Schedule of Other Comprehensive Income and Related Tax Effects

The gross amounts of each component of other comprehensive income and the related tax effects are as follows:

	Pre-tax				Tax Expense (Benefit)				Net of Tax
Three Months Ended September 30,	2021		2020		2021		2020		2021		2020
Investment securities available-for sale:
Change in net unrealized loss during period	$	(13.4)	$	(4.2)	$	(3.3)	$	(1.1)	$	(10.1)	$	(3.1)
Reclassification adjustment for net gain included in net income	(0.3)		(0.1)		(0.1)		—		(0.2)		(0.1)
Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity	(2.5)		—		(0.6)		—		(1.9)		—
Unrealized loss on derivatives	3.2		—		0.8		—		2.4		—
Defined benefits post-retirement benefit plan:
Change in net actuarial gains	—		(0.1)		—		—		—		(0.1)
Total other comprehensive (loss) income	$	(13.0)	$	(4.4)	$	(3.2)	$	(1.1)	$	(9.8)	$	(3.3)

	Pre-tax				Tax Expense (Benefit)				Net of Tax
Nine Months Ended September 30,	2021		2020		2021		2020		2021		2020
Investment securities available-for sale:
Change in net unrealized (loss) gains during period	$	(81.0)	$	69.9	$	(20.5)	$	18.7	$	(60.5)	$	51.2
Reclassification adjustment for net gain included in net income	(0.2)		(0.1)		(0.1)		—		(0.1)		(0.1)
Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity	22.3		—		5.7		—		16.6		—
Unrealized loss on derivatives	2.3		0.2		0.6		—		1.7		0.2
Defined benefits post-retirement benefit plan:
Change in net actuarial gains	—		(0.5)		—		(0.1)		—		(0.4)
Total other comprehensive (loss) income	$	(56.6)	$	69.5	$	(14.3)	$	18.6	$	(42.3)	$	50.9

Schedule of Accumulated Other Comprehensive Income (Loss)

The components of accumulated other comprehensive income, net of related tax effects, are as follows:

	September 30, 2021		December 31, 2020
Net unrealized (loss) gain on investment securities available-for-sale	$	(4.0)	$	56.8
Net unrealized gain on investment securities transferred to held-to-maturity	16.6		—
Net unrealized gain (loss) on derivatives	1.7		(0.2)
Net accumulated other comprehensive gains	$	14.3	$	56.6