Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment [Member]	Treasury Stock	AOCI Attributable to Parent	AOCI Attributable to Parent Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance at Dec. 31, 2018	$ 226.0	$ 0.6	$ 547.4	$ 829.8	$ (0.1)	$ (692.2)	$ (459.6)	$ 0.1
Balance, shares at Dec. 31, 2018		48,808,239
Balance, shares at Dec. 31, 2018						12,745,485
Accounting Standards Update [Extensible List]				us-gaap:AccountingStandardsUpdate201712Member			us-gaap:AccountingStandardsUpdate201712Member
Stock issuance, net, shares	709,671
Cash dividends - per common share	$ (36.0)			$ (36.0)
Share based employee compensation			8.3
Net earnings (loss)	214.5			214.5
Other comprehensive income (loss)	83.4						$ 83.4
Acquisition of treasury stock	(131.3)					$ (131.3)
Acquisition of treasury stock, shares		(1,525,562)				1,525,562
Balance at Dec. 31, 2019	$ 364.9	$ 0.6	555.7	1,008.2		$ (823.5)	(376.1)
Balance, shares at Dec. 31, 2019		47,992,348
Balance, shares at Dec. 31, 2019						14,271,047
Stock issuance, net, shares	335,936
Cash dividends - per common share	$ (39.3)			(39.3)
Share based employee compensation			2.0
Net earnings (loss)	(99.1)			(99.1)
Other comprehensive income (loss)	266.8						266.8
Restricted stock issued to employees in connection with acquisition			(4.0)			$ 4.0
Restricted stock issued to employees in connection with acquisition, shares		94,230				(94,230)
Acquisition of treasury stock	(44.4)					$ (44.4)
Acquisition of treasury stock, shares		(508,693)				508,693
Balance at Dec. 31, 2020	$ 450.9	$ 0.6	553.7	869.8		$ (863.9)	(109.3)
Balance, shares at Dec. 31, 2020	47,913,821	47,913,821
Balance, shares at Dec. 31, 2020						14,685,510
Stock issuance, net			0.1			$ (0.1)
Stock issuance, net, shares	173,379					2,445
Cash dividends - per common share	$ (41.6)			(41.6)
Share based employee compensation			7.5
Net earnings (loss)	183.2			183.2
Other comprehensive income (loss)	(0.3)						(0.3)
Acquisition of treasury stock	(80.0)					$ (80.0)
Acquisition of treasury stock, shares		(784,901)				784,901
Balance at Dec. 31, 2021	$ 519.7	$ 0.6	$ 561.3	$ 1,011.4		$ (944.0)	$ (109.6)
Balance, shares at Dec. 31, 2021	47,302,299	47,302,299
Balance, shares at Dec. 31, 2021						15,472,856