Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill And Intangible Assets [Line Items]
Amortization of intangible assets	$ 2,259,000	$ 2,176,000	$ 1,544,000	$ 2,491,000	$ 1,519,000	$ 1,511,000	$ 1,409,000	$ 398,000	$ 8,470,000	$ 4,837,000	$ 1,373,000
Accumulated amortization	16,252,000				7,782,000				16,252,000	7,782,000
Impairment related and other	3,525,000	470,000	127,000	170,000	334,000	655,000	141,000		4,292,000	1,130,000	109,000
GovDelivery
Goodwill And Intangible Assets [Line Items]
Intangible assets impairment charges										400,000
Goodwill impairment charges										300,000
Accumulated amortization					5,400,000					5,400,000
Goodwill and other intangible assets impairment Charges										700,000
Impairment related and other										700,000
Bolt
Goodwill And Intangible Assets [Line Items]
Decrease in intangible assets										(10,900,000)
Goodwill increased (decreased) amount										$ 10,200,000