Debt - Schedule of Company's Debt (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Principal amount	$ 363,200	$ 436,059
Unamortized discount	(1,782)	(14,037)
Debt issuance costs	(5,010)	(7,065)
Net carrying value	356,408	414,957
Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Principal amount	360,000	0
Unamortized discount	(1,782)	0
Debt issuance costs	(5,010)	0
Net carrying value	353,208	0
TaxACT - HD Vest 2015 Credit Facility [Member]
Debt Instrument [Line Items]
Principal amount	0	260,000
Unamortized discount	0	(7,124)
Debt issuance costs	0	(5,295)
Net carrying value	0	247,581
Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Principal amount	0	172,859
Unamortized discount	0	(6,913)
Debt issuance costs	0	(1,770)
Net carrying value	0	164,176
President [Member] | Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Principal amount	3,200	3,200
Unamortized discount	0	0
Debt issuance costs	0	0
Net carrying value	$ 3,200	$ 3,200