Pension and Retirement Plans (Detail) - Fair value of the assets held by the UK pension plan by asset category - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	$ 9,301	$ 10,094
Fair Value Measurements Using Inputs Considered as Level I
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	324	352
Fair Value Measurements Using Inputs Considered as Level II
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	8,977	9,742
Fair Value Measurements Using Inputs Considered as Level III
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	0	0
Cash on deposit
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	324	352
Cash on deposit | Fair Value Measurements Using Inputs Considered as Level I
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	324	352
Cash on deposit | Fair Value Measurements Using Inputs Considered as Level II
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	0	0
Cash on deposit | Fair Value Measurements Using Inputs Considered as Level III
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	0	0
Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	8,977	9,742
Pooled Funds | Fair Value Measurements Using Inputs Considered as Level I
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	0	0
Pooled Funds | Fair Value Measurements Using Inputs Considered as Level II
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	8,977	9,742
Pooled Funds | Fair Value Measurements Using Inputs Considered as Level III
Defined Benefit Plan Disclosure [Line Items]
Plan assets fair value	$ 0	$ 0