Investments - Summary of Unrealized Loss Position (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	$ 7,658
Unrealized Losses, Less than 12 Months	15
Fair Value, 12 Months or More
Unrealized Losses, 12 Months or More
Fair Value	7,658
Unrealized Losses	15
U.S. Treasury Securities, Obligations of U.S. Government Agencies and Municipals [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	3,168
Unrealized Losses, Less than 12 Months	4
Fair Value, 12 Months or More
Unrealized Losses, 12 Months or More
Fair Value	3,168
Unrealized Losses	4
Corporate Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	4,490
Unrealized Losses, Less than 12 Months	11
Fair Value, 12 Months or More
Unrealized Losses, 12 Months or More
Fair Value	4,490
Unrealized Losses	$ 11