Derivative Instruments - Notional Amounts Outstanding under Foreign Currency Contracts (Detail) - Not Designated as Hedging Instrument - Foreign Exchange Contract - USD ($) $ in Thousands	Mar. 31, 2016	Sep. 30, 2015
Derivative [Line Items]
Foreign exchange contracts	$ 116	$ 89
Foreign exchange contracts	(116)	(36)
Buy Currency, British Pound; Sell Currency, Norwegian Krone
Derivative [Line Items]
Foreign exchange contracts	2
Foreign exchange contracts	0
Buy Currency, British Pound; Sell Currency, Swedish Krona
Derivative [Line Items]
Foreign exchange contracts	2
Foreign exchange contracts	0
Buy Currency, Korean Won; Sell Currency, U.S. Dollar
Derivative [Line Items]
Foreign exchange contracts	0
Foreign exchange contracts	(8)
Buy Currency, U.S. Dollar; Sell Currency, Korean Won
Derivative [Line Items]
Foreign exchange contracts		0
Foreign exchange contracts		(6)
Buy Currency, British Pound; Sell Currency, Euro
Derivative [Line Items]
Foreign exchange contracts	0	0
Foreign exchange contracts	(2)	(29)
Buy Currency, Korean Won; Sell Currency, Singapore Dollar
Derivative [Line Items]
Foreign exchange contracts	0
Foreign exchange contracts	0
Buy Currency, U.S. Dollar; Sell Currency, Taiwan Dollar
Derivative [Line Items]
Foreign exchange contracts	2	0
Foreign exchange contracts	0	(1)
Buy Currency, U.S. Dollar; Sell Currency, Chinese Yuan
Derivative [Line Items]
Foreign exchange contracts	0	15
Foreign exchange contracts	(30)	0
Buy Currency, U.S. Dollar; Sell Currency, British Pound
Derivative [Line Items]
Foreign exchange contracts	0	32
Foreign exchange contracts	(68)	0
Buy Currency, Euro; Sell Currency U.S. Dollar
Derivative [Line Items]
Foreign exchange contracts	110	40
Foreign exchange contracts	0	0
Buy Currency, U.S. Dollar; Sell Currency, Japanese Yen, One
Derivative [Line Items]
Foreign exchange contracts	0	0
Foreign exchange contracts	(5)	0
Buy Currency, U.S. Dollar; Sell Currency, Japanese Yen, Two
Derivative [Line Items]
Foreign exchange contracts		2
Foreign exchange contracts		0
Buy Currency, Korean Won; Sell Currency, Japanese Yen
Derivative [Line Items]
Foreign exchange contracts	0
Foreign exchange contracts	(1)
Buy Currency, Singapore Dollar; Sell Currency, U.S. Dollar
Derivative [Line Items]
Foreign exchange contracts	0
Foreign exchange contracts	(2)
Buy Currency, U.S. Dollar; Sell Currency, Israeli Shekel
Derivative [Line Items]
Foreign exchange contracts	0	0
Foreign exchange contracts	0	0
Long | Buy Currency, British Pound; Sell Currency, Norwegian Krone
Derivative [Line Items]
Notional Amount	425
Long | Buy Currency, British Pound; Sell Currency, Swedish Krona
Derivative [Line Items]
Notional Amount	252
Long | Buy Currency, Korean Won; Sell Currency, U.S. Dollar
Derivative [Line Items]
Notional Amount	2,212
Long | Buy Currency, U.S. Dollar; Sell Currency, Korean Won
Derivative [Line Items]
Notional Amount		1,543
Long | Buy Currency, British Pound; Sell Currency, Euro
Derivative [Line Items]
Notional Amount	1,678	2,157
Long | Buy Currency, Korean Won; Sell Currency, Singapore Dollar
Derivative [Line Items]
Notional Amount	22
Long | Buy Currency, U.S. Dollar; Sell Currency, Taiwan Dollar
Derivative [Line Items]
Notional Amount	675	662
Long | Buy Currency, U.S. Dollar; Sell Currency, Chinese Yuan
Derivative [Line Items]
Notional Amount	5,959	5,177
Long | Buy Currency, U.S. Dollar; Sell Currency, British Pound
Derivative [Line Items]
Notional Amount	7,300	4,308
Long | Buy Currency, Euro; Sell Currency U.S. Dollar
Derivative [Line Items]
Notional Amount	18,525	9,300
Long | Buy Currency, U.S. Dollar; Sell Currency, Japanese Yen, One
Derivative [Line Items]
Notional Amount	2,081	425
Long | Buy Currency, U.S. Dollar; Sell Currency, Japanese Yen, Two
Derivative [Line Items]
Notional Amount		1,336
Long | Buy Currency, Korean Won; Sell Currency, Japanese Yen
Derivative [Line Items]
Notional Amount	44
Long | Buy Currency, Singapore Dollar; Sell Currency, U.S. Dollar
Derivative [Line Items]
Notional Amount	629
Long | Buy Currency, U.S. Dollar; Sell Currency, Israeli Shekel
Derivative [Line Items]
Notional Amount	59	457
Short | Buy Currency, British Pound; Sell Currency, Norwegian Krone
Derivative [Line Items]
Notional Amount	3,600
Short | Buy Currency, British Pound; Sell Currency, Swedish Krona
Derivative [Line Items]
Notional Amount	2,100
Short | Buy Currency, Korean Won; Sell Currency, U.S. Dollar
Derivative [Line Items]
Notional Amount	2,580,000
Short | Buy Currency, U.S. Dollar; Sell Currency, Korean Won
Derivative [Line Items]
Notional Amount		1,852,000
Short | Buy Currency, British Pound; Sell Currency, Euro
Derivative [Line Items]
Notional Amount	1,500	1,600
Short | Buy Currency, Korean Won; Sell Currency, Singapore Dollar
Derivative [Line Items]
Notional Amount	30
Short | Buy Currency, U.S. Dollar; Sell Currency, Taiwan Dollar
Derivative [Line Items]
Notional Amount	22,000	22,000
Short | Buy Currency, U.S. Dollar; Sell Currency, Chinese Yuan
Derivative [Line Items]
Notional Amount	39,000	33,000
Short | Buy Currency, U.S. Dollar; Sell Currency, British Pound
Derivative [Line Items]
Notional Amount	10,410	6,520
Short | Buy Currency, Euro; Sell Currency U.S. Dollar
Derivative [Line Items]
Notional Amount	20,800	8,253
Short | Buy Currency, U.S. Dollar; Sell Currency, Japanese Yen, One
Derivative [Line Items]
Notional Amount	236,000	51,000
Short | Buy Currency, U.S. Dollar; Sell Currency, Japanese Yen, Two
Derivative [Line Items]
Notional Amount		160,000
Short | Buy Currency, Korean Won; Sell Currency, Japanese Yen
Derivative [Line Items]
Notional Amount	0
Short | Buy Currency, Singapore Dollar; Sell Currency, U.S. Dollar
Derivative [Line Items]
Notional Amount	860
Short | Buy Currency, U.S. Dollar; Sell Currency, Israeli Shekel
Derivative [Line Items]
Notional Amount	$ 227	$ 1,800