Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidated Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings	$ (3,273)	$ 4,277	$ (18,521)	$ (4,655)
Unrealized gain (loss) on short-term investments	167	210	329	1,017
Changes in pension plan asset and benefit obligation	23	1	22	2
Tax effect of the above-listed adjustments	(68)	(75)	(127)	(407)
Total comprehensive (loss) income	(3,151)	4,413	(18,297)	(4,043)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings	(14,613)	(7,035)	(17,243)	(12,090)
Total comprehensive (loss) income	(14,613)	(7,035)	(17,243)	(12,090)
Parent Company Only (issuer) [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings	(3,273)	4,277	(18,521)	(4,655)
Unrealized gain (loss) on short-term investments	167	210	329	1,017
Changes in pension plan asset and benefit obligation	23	1	22	2
Tax effect of the above-listed adjustments	(68)	(75)	(127)	(407)
Total comprehensive (loss) income	(3,151)	4,413	(18,297)	(4,043)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings	15,770	7,035	17,381	12,090
Total comprehensive (loss) income	15,770	$ 7,035	17,381	$ 12,090
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings	(1,157)		(138)
Total comprehensive (loss) income	$ (1,157)		$ (138)

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
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e557-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51831255

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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