Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidated Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings		$ (4,967)	$ 7,669	$ (9,622)	$ 24,486
Unrealized (loss) gain on short-term investments		(494)	12	523	(7)
Unrealized realized gain					24
Changes in pension plan assets and benefit obligations		1	4	3	4
Tax effect		178	(6)	(229)	3
Total comprehensive (loss) income		(5,282)	7,679	(9,325)	24,510
Parent Company Only (issuer) [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings		(4,967)	7,669	(9,622)	24,486
Unrealized (loss) gain on short-term investments		(494)	12	523	(7)
Unrealized realized gain					24
Changes in pension plan assets and benefit obligations		1	4	3	4
Tax effect		178	(6)	(229)	3
Total comprehensive (loss) income		(5,282)	7,679	(9,325)	24,510
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings	[1]	8,372	10,682	20,462	26,044
Total comprehensive (loss) income	[1]	8,372	10,682	20,462	26,044
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings		(8,372)	(10,682)	(20,462)	(26,044)
Total comprehensive (loss) income		$ (8,372)	$ (10,682)	$ (20,462)	$ (26,044)

[1] Foreign subsidiaries represent minor subsidiaries and are included in the guarantor subsidiaries' amounts.