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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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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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Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Long Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Debt Instrument [Line Items]
Total debt	$ 1,581,023us-gaap_LongTermDebt	$ 1,585,395us-gaap_LongTermDebt	$ 1,067,944us-gaap_LongTermDebt
Less: Current maturities	(14,406)us-gaap_LongTermDebtCurrent	(14,336)us-gaap_LongTermDebtCurrent	(12,403)us-gaap_LongTermDebtCurrent
Long-term debt	1,566,617us-gaap_LongTermDebtNoncurrent	1,571,059us-gaap_LongTermDebtNoncurrent	1,055,541us-gaap_LongTermDebtNoncurrent
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Total debt	299,182	299,123	298,949
7% Debentures, Due 2025
Debt Instrument [Line Items]
Total debt	124,508	124,500	124,478
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Total debt	228,194	228,184	228,157
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Total debt	395,410	395,309
Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Total debt	298,980	298,869
Term Loan Facility, Due 2018
Debt Instrument [Line Items]
Total debt	233,213	236,258	245,395
Trade Receivable Facility
Debt Instrument [Line Items]
Credit Facility			150,000
Other Notes
Debt Instrument [Line Items]
Other notes	1,536	3,152	965
Revolving Facility
Debt Instrument [Line Items]
Credit Facility			$ 20,000