Cash, Cash Equivalents and Investments - Additional Information (Detail) (USD $)	12 Months Ended		3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Equity securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash balance included foreign bank balance	$ 23,614,000	$ 29,452,000
Purchase of equity securities			2,136,000
Fair value			2,131,000
Gross unrealized loss			5,000
Gross realized gains on sale of debt securities	1,990,000	82,000
Gross realized losses on sale of debt securities	295,000	263,000
Maximum amount committed to invest in limited partnership	20,500,000
Contribution to limited partnership	19,886,000
Remaining amount of commitment in limited partnership	614,000
Received a stock distribution	2,193,000
Recorded a realized loss on stock distribution	65,000
Shares were trading investment were sold	2,128,000
Carrying value of investment	3,740,000
Estimated fair value of investment	$ 6,932,000