Fair Value Measurements - Additional Information (Detail) (USD $)		3 Months Ended
	Jun. 30, 2012	Mar. 31, 2012 Auction Rate Securities	Mar. 31, 2012 Auction Rate Securities Securities Redeemed at Less Than Par Value	Mar. 31, 2012 Auction Rate Securities Securities Redeemed at Par Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net proceeds from liquidation of auction rate security		$ 25,400,000
Par value of auction rate securities redeemed			29,500,000	24,900,000
Loss on liquidation of the securities		3,200,000
Impairment on auction rate securities		900,000
Derivative instruments, carrying value	$ 100,000