Long-Term Debt (Schedule Of Long-Term Debt Instruments) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Debt Instrument [Line Items]
Unsecured senior notes	$ 450,000		$ 250,000
Acquisition notes payable	93		1,260
Total debt	450,093		251,260
Less current portion	(93)	(1,227)	(1,227)
Long-term debt	$ 450,000	$ 250,033	$ 250,033

The amount of acquisition cost of a business combination allocated to notes payables and long-term debt assumed from the acquired entity.

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

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