Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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No definition available.

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Financial Instruments - Summary of Carrying Amounts and Estimated Fair Values of Other Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Feb. 13, 2017	Sep. 09, 2013	Mar. 23, 2012
USD Interest Rate Swap Contract One [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, Notional Amount	$ 50,000
Liabilities:
Derivative, Fixed Interest Rate	2.878%
USD Interest Rate Swap Contract Two [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, Notional Amount	$ 50,000
Liabilities:
Derivative, Fixed Interest Rate	2.878%
Carrying Amount
Assets:
Cash and cash equivalents	$ 72,819	$ 53,533
Fair Value
Assets:
Cash and cash equivalents	72,819	53,533
Bank Borrowings [Member] \| Carrying Amount
Liabilities:
Long term debt fair value	951,800	903,945
Bank Borrowings [Member] \| Fair Value
Liabilities:
Long term debt fair value	951,800	903,945
Senior Notes [Member] \| 5½% Senior Notes [Member]
Liabilities:
Stated interest rate				5.50%
Senior Notes [Member] \| 5% Senior Notes [Member]
Liabilities:
Stated interest rate					5.00%
Senior Notes [Member] \| Four and Three Quarters Percent Senior Notes due 2025 [Member]
Liabilities:
Stated interest rate			4.75%
Senior Notes [Member] \| Three and One Quarter Percent Senior Notes due 2025 [Member]
Liabilities:
Stated interest rate			3.25%
Senior Notes [Member] \| Carrying Amount \| 5½% Senior Notes [Member]
Liabilities:
Long term debt fair value	300,000	300,000
Senior Notes [Member] \| Carrying Amount \| Four and Three Quarters Percent Senior Notes due 2025 [Member]
Liabilities:
Long term debt fair value	300,000	300,000
Senior Notes [Member] \| Carrying Amount \| Three and One Quarter Percent Senior Notes due 2025 [Member]
Liabilities:
Long term debt fair value	744,380	780,325
Senior Notes [Member] \| Fair Value \| 5½% Senior Notes [Member]
Liabilities:
Long term debt fair value	301,761	308,301
Senior Notes [Member] \| Fair Value \| Four and Three Quarters Percent Senior Notes due 2025 [Member]
Liabilities:
Long term debt fair value	284,517	309,390
Senior Notes [Member] \| Fair Value \| Three and One Quarter Percent Senior Notes due 2025 [Member]
Liabilities:
Long term debt fair value	$ 746,591	$ 813,793