CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Non-controlling Interests [Member]	Total
Balance at Dec. 31, 2016	$ 4.8	$ 400.0	$ 1,419.1	$ (221.1)	$ (596.3)	$ 24.4	$ 1,030.9
Net income	0.0	0.0	195.1	0.0	0.0	3.9	199.0
Other comprehensive income (loss)	0.0	0.0	0.0	35.0	0.0	1.5	36.5
Dividends declared	0.0	0.0	(7.0)	0.0	0.0	0.0	(7.0)
Dividends paid to non-controlling interests	0.0	0.0	0.0	0.0	0.0	(2.4)	(2.4)
Issuance of shares pursuant to employee stock compensation plans	0.1	14.6	0.0	0.0	0.0	0.0	14.7
Income tax benefit arising from employee stock compensation plans	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Purchase of common stock for treasury	0.0	0.0	0.0	0.0	(0.7)	0.0	(0.7)
Stock-based compensation	0.0	8.1	0.0	0.0	0.0	0.0	8.1
Balance at Dec. 31, 2017	4.9	422.7	1,607.2	(186.1)	(597.0)	27.4	1,279.1
Net income	0.0	0.0	169.0	0.0	0.0	4.2	173.2
Other comprehensive income (loss)	0.0	0.0	0.0	(47.6)	0.0	(1.8)	(49.4)
Dividends declared	0.0	0.0	(7.1)	0.0	0.0	0.0	(7.1)
Dividends paid to non-controlling interests	0.0	0.0	0.0	0.0	0.0	(1.8)	(1.8)
Acquisition of non-controlling interest	0.0	0.0	0.0	0.0	0.0	0.1	0.1
Capital contribution from non-controlling interests	0.0	0.0	0.0	0.0	0.0	3.7	3.7
Issuance of shares pursuant to employee stock compensation plans	0.0	3.0	0.0	0.0	0.0	0.0	3.0
Purchase of common stock for treasury	0.0	0.0	0.0	0.0	(21.7)	0.0	(21.7)
Stock-based compensation	0.0	6.2	0.0	0.0	0.0	0.0	6.2
Balance at Dec. 31, 2018	4.9	431.9	1,769.1	(233.7)	(618.7)	31.8	1,385.3
Cumulative effect of accounting change | ASU 2018-02 [Member]	0.0	0.0	10.9	(10.9)	0.0	0.0	0.0
Net income	0.0	0.0	132.7	0.0	0.0	3.7	136.4
Other comprehensive income (loss)	0.0	0.0	0.0	(45.8)	0.0	0.0	(45.8)
Dividends declared	0.0	0.0	(7.0)	0.0	0.0	0.0	(7.0)
Dividends paid to non-controlling interests	0.0	0.0	0.0	0.0	0.0	(4.2)	(4.2)
Capital contribution from non-controlling interests	0.0	0.0	0.0	0.0	0.0	0.6	0.6
Issuance of shares pursuant to employee stock compensation plans	0.0	2.2	0.0	0.0	0.0	0.0	2.2
Purchase of common stock for treasury	0.0	0.0	0.0	0.0	(41.0)	0.0	(41.0)
Stock-based compensation	0.0	8.1	0.0	0.0	0.0	0.0	8.1
Balance at Dec. 31, 2019	$ 4.9	$ 442.2	1,905.7	(290.4)	$ (659.7)	$ 31.9	$ 1,434.6
Cumulative effect of accounting change | ASU 2018-02 [Member]			$ 10.9	$ (10.9)