Condensed Consolidated Statements Of Changes in Shareholders’ Equity - USD ($) $ in Millions	Common Stock	Common Stock Subscribed, Unissued	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Total
Balance at Dec. 31, 2019	$ 449.5		$ 694.0	$ (250.6)	$ 4.9	$ 897.8
Net income			21.4		0.1	21.5
Other comprehensive income (loss)				(3.4)	(0.3)	(3.7)
Stock issued	9.4					9.4
Stock purchased	(4.2)				(0.1)	(4.3)
Advance payments		$ 1.1				1.1
Dividends declared			(6.9)			(6.9)
Balance at Mar. 31, 2020	454.7	1.1	708.5	(254.0)	4.6	914.9
Balance at Dec. 31, 2019	449.5		694.0	(250.6)	4.9	897.8
Net income						93.2
Other comprehensive income (loss)						16.9
Balance at Sep. 30, 2020	452.3	1.0	766.5	(233.7)	4.3	990.4
Balance at Mar. 31, 2020	454.7	1.1	708.5	(254.0)	4.6	914.9
Net income			37.1			37.1
Other comprehensive income (loss)				9.6	0.2	9.8
Stock issued	3.6					3.6
Stock purchased	(4.6)				(0.6)	(5.2)
Advance payments		(0.6)				(0.6)
Dividends declared			(6.8)			(6.8)
Balance at Jun. 30, 2020	453.7	0.5	738.8	(244.4)	4.2	952.8
Net income			34.5		0.1	34.6
Other comprehensive income (loss)				10.7	0.1	10.8
Stock issued	3.1					3.1
Stock purchased	(4.5)				(0.1)	(4.6)
Advance payments		0.5				0.5
Dividends declared			(6.8)			(6.8)
Balance at Sep. 30, 2020	452.3	1.0	766.5	(233.7)	4.3	990.4
Balance at Dec. 31, 2020	452.1		725.1	(246.7)	4.5	935.0
Net income			47.2		0.1	47.3
Other comprehensive income (loss)				8.0	0.1	8.1
Stock issued	10.0					10.0
Stock purchased	(4.3)				(0.5)	(4.8)
Advance payments		1.1				1.1
Dividends declared			(6.9)			(6.9)
Balance at Mar. 31, 2021	457.8	1.1	765.4	(238.7)	4.2	989.8
Balance at Dec. 31, 2020	452.1		725.1	(246.7)	4.5	935.0
Net income						202.1
Other comprehensive income (loss)						46.6
Balance at Sep. 30, 2021	456.5	1.1	906.1	(200.1)	5.6	1,169.2
Balance at Mar. 31, 2021	457.8	1.1	765.4	(238.7)	4.2	989.8
Net income			80.1		0.2	80.3
Other comprehensive income (loss)				8.2		8.2
Stock issued	3.8					3.8
Stock purchased	(5.3)					(5.3)
Advance payments		(0.5)				(0.5)
Dividends declared			(6.8)			(6.8)
Balance at Jun. 30, 2021	456.3	0.6	838.7	(230.5)	4.4	1,069.5
Net income			74.3		0.2	74.5
Other comprehensive income (loss)				30.4	(0.1)	30.3
Stock issued	3.1				1.1	4.2
Stock purchased	(2.9)					(2.9)
Advance payments		0.5				0.5
Dividends declared			(6.9)			(6.9)
Balance at Sep. 30, 2021	$ 456.5	$ 1.1	$ 906.1	$ (200.1)	$ 5.6	$ 1,169.2