Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (Assets and Liabilities Measured at Fair Value on a Recurring Basis [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	$ 59,963	$ 47,011
U.S. government and government agency obligations [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	7,394	22,890
Mortgage-backed securities [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	5,545	8,216
Asset-backed securities [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	2,369	3,537
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	1,550
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | U.S. government and government agency obligations [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Mortgage-backed securities [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Asset-backed securities [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	58,413	47,011
Significant Other Observable Inputs (Level 2) [Member] | U.S. government and government agency obligations [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	7,394	22,890
Significant Other Observable Inputs (Level 2) [Member] | Mortgage-backed securities [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	5,545	8,216
Significant Other Observable Inputs (Level 2) [Member] | Asset-backed securities [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	2,369	3,537
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Significant Unobservable Inputs (Level 3) [Member] | U.S. government and government agency obligations [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Significant Unobservable Inputs (Level 3) [Member] | Mortgage-backed securities [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Significant Unobservable Inputs (Level 3) [Member] | Asset-backed securities [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Cash equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	40,100	4,402
Cash equivalents [Member] | Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Cash equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	40,100	4,402
Cash equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Available for sale equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	1,550
Available for sale equity securities [Member] | Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	1,550
Municipal bonds [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	1,175	3,059
Municipal bonds [Member] | Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Municipal bonds [Member] | Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	1,175	3,059
Municipal bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Corporate bonds [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	1,830	4,907
Corporate bonds [Member] | Quoted Prices in Active Markets for Identical Instruments (Level 1) [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value
Corporate bonds [Member] | Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	1,830	4,907
Corporate bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Available-for-sale debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value