Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidated Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings		$ (17,058)	$ (4,967)	$ 4,277	$ (8,932)	$ 2,438	$ 7,669	$ 6,454	$ 10,363	$ (26,680)	$ 26,924	$ 32,688
Unrealized gain (loss) on short-term investments										241	(641)	(285)
Other unrealized gain (loss)											24	(24)
Changes in pension plan assets and benefit obligations										(39)	7	17
Tax effect										(113)	254	105
Total comprehensive (loss) income										(26,591)	26,568	32,501
Parent Company Only (issuer) [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings										(26,680)	26,924	32,688
Unrealized gain (loss) on short-term investments										241	(641)	(285)
Other unrealized gain (loss)											24	(24)
Changes in pension plan assets and benefit obligations										(39)	7	17
Tax effect										(113)	254	105
Total comprehensive (loss) income										(26,591)	26,568	32,501
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings	[1]									22,182	31,225	38,740
Total comprehensive (loss) income	[1]									22,182	31,225	38,740
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) earnings										(22,182)	(31,225)	(38,740)
Total comprehensive (loss) income										$ (22,182)	$ (31,225)	$ (38,740)

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