Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended													12 Months Ended	1 Months Ended		12 Months Ended			9 Months Ended	12 Months Ended
	Apr. 30, 2008	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2013 Maximum [Member]	Dec. 31, 2013 Telecommunication services [Member]	Sep. 30, 2012 Telecommunication services [Member]	Dec. 31, 2013 Computer support services [Member]	May 31, 2012 Computer support services [Member]	Dec. 31, 2013 Satellite services [Member]	Oct. 31, 2010 Satellite services [Member]	Dec. 31, 2011 Network Maintenance Services [Member]	Dec. 31, 2013 Paging equipment assets [Member]	Dec. 31, 2013 Headquarter Office Space Lease [Member]	Jun. 30, 2011 Office space lease [Member]	Nov. 30, 2009 Office space lease [Member]	Dec. 31, 2013 Office space lease [Member]	Dec. 31, 2013 Office space lease [Member] Texas [Member]	Dec. 31, 2013 Office space lease [Member] Minnesota [Member]	Sep. 30, 2013 Office space lease [Member] New York [Member]	Dec. 31, 2013 Office space lease [Member] New York [Member]	Dec. 31, 2013 Office space lease [Member] New Hampshire [Member]	Dec. 31, 2013 Office space lease [Member] Florida [Member]	Dec. 31, 2013 Office space lease [Member] Australia [Member]
Commitments And Contingencies [Line Items]
Annual contractual obligation cost									$ 100,000		$ 200,000		$ 500,000
Contract term of managed service-hosting provider										2 years		3 years		3 years	3 years
Amended contract year	3 years
Contractual obligations includes both fixed and variable				100,000
Lease commencement year																	April 2010			October 2011
Rent expense				19,100,000	20,400,000	26,100,000											1,400,000				2,500,000			3,600,000
Lease incentives				180,000	332,000												400,000							400,000
Duration of lease term																		5 years	5 years				10 years
Remaining commitment													900,000				400,000					1,500,000		100,000	800,000	100,000	400,000
Remaining contractual obligations																100,000					1,600,000
Rent abatements																					200,000
LOC contract period requirement							1 year	3 years
Deposits related to letter of credit are included in other assets				100,000
Reduced LOC		$ 100,000	$ 200,000
Operating leases, term of contract							1 month	5 years