Fair Value Of Financial Instruments (Schedule Of Carrying Amounts And Estimated Fair Values Of Financial Instruments) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash surrender value of life insurance policies	$ 11.9		$ 10.6
Deferred compensation plan liabilities	3.3		2.2
Earn-out Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related contingent consideration	143.6		80.5
Auction Rate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Auction rate securities	14.4	[1]	13.6	[1]
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash surrender value of life insurance policies	11.9		10.6
Carrying Amount [Member] | Earn-out Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related contingent consideration	143.6		80.5
Carrying Amount [Member] | 7.625% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
7.625% senior notes	150.0		150.0
Carrying Amount [Member] | Convertible Debt [Member] | Original 4.0% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior convertible notes	9.7		9.7
Carrying Amount [Member] | Convertible Debt [Member] | Original 4.25% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior convertible notes	3.0		3.0
Carrying Amount [Member] | Convertible Debt [Member] | New 4.0% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior convertible notes	100.9		98.2
Carrying Amount [Member] | Convertible Debt [Member] | New 4.25% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior convertible notes	92.1		89.9
Carrying Amount [Member] | Auction Rate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Auction rate securities	14.4		13.6
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash surrender value of life insurance policies	11.9		10.6
Fair Value [Member] | Earn-out Arrangements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related contingent consideration	143.6		80.5
Fair Value [Member] | 7.625% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
7.625% senior notes	154.9		156.4
Fair Value [Member] | Convertible Debt [Member] | Original 4.0% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior convertible notes	15.9		12.5
Fair Value [Member] | Convertible Debt [Member] | Original 4.25% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior convertible notes	5.1		4.0
Fair Value [Member] | Convertible Debt [Member] | New 4.0% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior convertible notes	101.5		99.4
Fair Value [Member] | Convertible Debt [Member] | New 4.25% Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior convertible notes	92.7		91.1
Fair Value [Member] | Auction Rate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Auction rate securities	14.4		13.6
Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member] | Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan liabilities	3.3		2.2
Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan liabilities	$ 3.3		$ 2.2

[1] The Company’s auction rate securities maintain split ratings. For purposes of this table, securities are categorized according to their lowest rating.