Summarized Financial Information for StarCite (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Business Combination, Separately Recognized Transactions [Line Items]
Total Assets	$ 447,759				$ 306,820				$ 447,759	$ 306,820	$ 280,989
Total Liabilities	105,344				51,945				105,344	51,945
Total Stockholders' Equity	265,898				245,884				265,898	245,884
Revenue	43,584	45,489	42,822	34,698	34,435	33,427	33,531	32,044	166,593	133,437	109,213
Net (loss)	14,837	20,954	(5,342)	(6,868)	19,160	(2,622)	(2,979)	16,242	23,581	29,801	47,908
Star Cite
Business Combination, Separately Recognized Transactions [Line Items]
Total Assets					51,335					51,335	48,869
Total Liabilities					32,924					32,924	32,936
Total Stockholders' Equity					18,411					18,411	15,933
Revenue										44,968	44,488
Expenses										(50,324)	(49,364)
Net (loss)										$ (5,356)	$ (4,876)