Severance and Other Exit Costs - Summary of Aggregate Activity Related to Company's Facilities Exit Costs Accrual and Severance Accrual (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Facilities Closing
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 9,020
Facility adjustments	1,055
Sublease income received	188
Cash paid	(1,497)
Ending Balance	8,766
Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	1,559
Severance charges	4,572
Cash paid	(1,834)
Ending Balance	4,297
Web presence segment | Facilities Closing
Restructuring Reserve [Roll Forward]
Beginning Balance	273
Facility adjustments	(10)
Sublease income received	188
Cash paid	(246)
Ending Balance	205
Web presence segment | Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	633
Severance charges	2,345
Cash paid	(641)
Ending Balance	2,337
Email marketing segment | Facilities Closing
Restructuring Reserve [Roll Forward]
Beginning Balance	8,747
Facility adjustments	1,065
Sublease income received	0
Cash paid	(1,251)
Ending Balance	8,561
Email marketing segment | Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	926
Severance charges	2,227
Cash paid	(1,193)
Ending Balance	$ 1,960