Schedule II - Valuation and Qualifying Accounts (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for doubtful accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 6.6	$ 4.8	$ 4.4
Amounts Recorded in Earnings	2.7	1.0	0.5
Adjustments	(2.6)	0.8	(0.1)
Balance at End of Year	6.7	6.6	4.8
Allowance for estimated policy cancellations [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	4.0	5.2	4.3
Amounts Recorded in Earnings	(0.2)	(1.6)	0.9
Adjustments	0.4	0.4
Balance at End of Year	4.2	4.0	5.2
Accumulated amortization of expiration lists, noncompete agreements and trade names [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	419.3	321.3	247.7
Amounts Recorded in Earnings	125.2	99.0	79.3
Adjustments	(0.4)	(1.0)	(5.7)
Balance at End of Year	$ 544.1	$ 419.3	$ 321.3