Long-Term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Debt Instrument [Line Items]
Total debt - principal	$ 2,704,068	$ 2,317,723	$ 2,949,557
Less unamortized debt issuance costs	12,492	13,109	16,196
Debt long term and short term less unamortized debt issuance costs combined amount	2,691,576	2,304,614	2,933,361
Less current portion	578,001	170,214	758,652
Long-term debt	2,113,575	2,134,400	2,174,709
Bank debt [Member]
Debt Instrument [Line Items]
Total debt - principal	1,352,731	951,800	1,268,497
5% Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Total debt - principal	$ 0	$ 0	$ 280,000
Senior note interest rate (percent)			5.00%
5 1/2% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Total debt - principal	$ 300,000	$ 300,000	$ 300,000
Senior note interest rate (percent)	5.50%	5.50%	5.50%
4 3/4% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Total debt - principal	$ 300,000	$ 300,000	$ 300,000
Senior note interest rate (percent)	4.75%	4.75%	4.75%
3 1/4% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Total debt - principal	$ 729,170	$ 744,380	$ 801,060
Senior note interest rate (percent)	3.25%	3.25%	3.25%
Finance leases [Member]
Debt Instrument [Line Items]
Total debt - principal	$ 22,167	$ 21,543	$ 0
Revolving Loan [Member] \| Bank debt [Member]
Debt Instrument [Line Items]
Total debt - principal	506,000	0	415,000
Less current portion	506,000
U S Term Loans [Member] \| Bank debt [Member]
Debt Instrument [Line Items]
Total debt - principal	800,000	800,000	800,000
Less current portion	40,000
Canadian Term Loans [Member] \| Bank debt [Member]
Debt Instrument [Line Items]
Total debt - principal	15,825	22,103	23,362
Other Foreign Bank Revolving And Term Loans [Member] \| Bank debt [Member]
Debt Instrument [Line Items]
Total debt - principal	30,906	$ 129,697	$ 30,135
Less current portion	30,900
Finance leases [Member]
Debt Instrument [Line Items]
Less current portion	$ 1,100

Debt Long Term and Short Term Less Unamortized Debt Issuance Expense Combined Amount

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section S99
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- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts 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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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