Supplemental Cash Flow Information (Schedule Of Interest Paid) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Interest Paid [Line Items]
Total interest paid	$ 18.8	$ 18.7
Junior Subordinated Debentures [Member]
Interest Paid [Line Items]
Total interest paid	16.3	15.9
Other Indebtedness [Member]
Interest Paid [Line Items]
Total interest paid	$ 2.5	$ 2.8