Investments - Amortized Cost, Unrealized Holding Gains (Losses) and Fair Value of Available-for-Sale Securities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 42,833	$ 42,522
Unrealized Gains	82	184
Unrealized Losses	(96)	(97)
Fair Value	42,819	42,609
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,827	3,049
Unrealized Gains	10	15
Unrealized Losses	(3)	(5)
Fair Value	1,834	3,059
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,321	4,896
Unrealized Gains	6	17
Unrealized Losses	(11)	(6)
Fair Value	4,316	4,907
U.S. government and government agency obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	25,084	22,889
Unrealized Gains	10	28
Unrealized Losses	(28)	(27)
Fair Value	25,066	22,890
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,226	8,149
Unrealized Gains	43	118
Unrealized Losses	(46)	(51)
Fair Value	5,223	8,216
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,375	3,539
Unrealized Gains	13	6
Unrealized Losses	(8)	(8)
Fair Value	$ 6,380	$ 3,537