Allocation of Purchase Price for Acquisitions and Enterprise Value of Channel Intelligence (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Net assets acquired:
Goodwill	$ 97,301	$ 90,466
Superior Access
Net assets acquired:
Goodwill	2,654
Customer lists (5-11 year life)	4,000
Trademarks, trade names and domain names (5-11 year life)	1,100
Technology (5 year life)	1,300
Other net assets (liabilities)	(343)
Purchase price allocation assets acquired	8,711
KMI
Net assets acquired:
Goodwill	6,835
Customer lists (5-11 year life)	2,900
Trademarks, trade names and domain names (5-11 year life)	300
Technology (5 year life)	400
Other net assets (liabilities)	1,165
Purchase price allocation assets acquired	$ 11,600