Condensed Consolidating Statements of Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Condensed Statement Of Income Captions [Line Items]
Net income	$ 14,855	$ 10,152
Foreign currency translation adjustment	8,626	2,503
Comprehensive income	23,481	12,655
Eliminations
Condensed Statement Of Income Captions [Line Items]
Net income	(8,983)
Comprehensive income	(8,983)
Guarantors
Condensed Statement Of Income Captions [Line Items]
Net income	20,100	6,246
Comprehensive income	20,100	6,246
Non-Guarantors
Condensed Statement Of Income Captions [Line Items]
Net income	3,738	3,906
Foreign currency translation adjustment	8,626	2,503
Comprehensive income	$ 12,364	$ 6,409

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831270

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831223

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
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-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e557-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51831255

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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