Summary of Significant Accounting Policies - Policies Narrative (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jan. 01, 2018
Lessee, Lease, Description [Line Items]
Temporary Equity, Accretion to Redemption Value, Adjustment	$ 0	$ 5,977	$ 0
Impairment of indefinite-live intangible assets (excluding goodwill)	50,900
Right-of-use assets, net	10,151	0		$ 6,600
Operating lease liability	9,088			9,100
Impact of adoption of new accounting standard				(1,636)	$ 1,851
Leases, other				900
Payments for Repurchase of Redeemable Noncontrolling Interest	24,945	0	0
Software development costs	7,400	6,500	3,500
Adjustment of redeemable noncontrolling interests to redemption value	2,517	(5,977)
Redeemable noncontrolling interest, equity, redemption value		24,900
Advertising expense	54,500	$ 53,300	$ 51,700
Prepaid advertising costs	$ 300
Retained earnings
Lessee, Lease, Description [Line Items]
Impact of adoption of new accounting standard				$ (1,636)	$ 1,851