Cash, Cash Equivalents, and Investments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Cash balance included foreign bank balance	$ 32,096,000	$ 23,614,000
Gross realized gains on sale of investments	508,000	1,990,000
Gross realized losses on sale of investments	194,000	295,000
Maximum amount committed to invest in limited partnership	20,500,000
Contribution to limited partnership	19,886,000
Shares were trading investment were sold	347,000	2,128,000
Cash distributions	1,422,000
Remaining amount of commitment in limited partnership	614,000
Investment expiration date	Dec. 31, 2015
Number of contributions made during the period	0
Received a stock distribution	362,000	2,193,000
Recorded a realized loss on stock distribution	15,000	65,000
Carrying value of investment	1,956,000	3,740,000
Estimated fair value of investment	4,315,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Purchase of equity securities		2,136,000
Aggregate fair value of liquidated share	1,429,000
Realized loss	702,000
Net unrealized loss		$ 5,000