Fair Value of Senior Notes (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013
Series 2005A Tranche B [Member]
Fair Value of Financial Instruments [Line Items]
Fair Value of Senior Notes	$ 59,897
Series 2005A Tranche C [Member]
Fair Value of Financial Instruments [Line Items]
Fair Value of Senior Notes	61,047
Series 2007A Tranche A [Member]
Fair Value of Financial Instruments [Line Items]
Fair Value of Senior Notes	9,814
Series 2007A Tranche B [Member]
Fair Value of Financial Instruments [Line Items]
Fair Value of Senior Notes	8,684
Series 2007A Tranche C [[Member]
Fair Value of Financial Instruments [Line Items]
Fair Value of Senior Notes	26,340
Series 2007A Tranche D [Member]
Fair Value of Financial Instruments [Line Items]
Fair Value of Senior Notes	$ 40,369