Long-Term Obligations - Summary of Long-Term Obligations (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total long-term obligations	$ 1,636,200	$ 1,545,149
Less: current portion	(13,231)	(13,059)
Long-term obligations, excluding current portion	1,622,969	1,532,090
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Total long-term obligations	3,653	3,276
Term Loan Credit Agreement [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Total long-term obligations	792,664	1,196,505
Senior Notes - Due 2026 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Total long-term obligations	493,897
Senior Notes - Due 2023 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Total long-term obligations	$ 345,986	$ 345,368

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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

+ 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))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

+ 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 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Amount of long-term debt and capital lease obligations including current maturities.

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