Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	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 Segment	Dec. 31, 2012	Dec. 31, 2011
Summary Of Significant Accounting Policies [Line Items]
Share-based compensation									$ 11,111	$ 6,758	$ 3,285
Net income (loss)	52,976	6,466	(1,445)	(3,542)	4,080	7,868	(6,898)	18,453	54,455	23,503	(4,257)
Income tax (benefit) expense	(37,769)	210	(12)	47					(37,524)	(13,730)	214
Goodwill	159,342				129,428				159,342	129,428
Number of operating segments									2
Impairment of goodwill									0
Amounts due from financial intermediaries classified as cash and cash equivalents	1,623				2,356				1,623	2,356
Restricted cash	0				0				0	0
Allowance for doubtful accounts	104				134				104	134
Advertising expense									86,165	66,049	54,567
Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of tax benefit likely to be realized upon settlement									50.00%
Federal
Summary Of Significant Accounting Policies [Line Items]
Net operating loss carryforwards, expiration amount	7,894								7,894
State
Summary Of Significant Accounting Policies [Line Items]
Net operating loss carryforwards, expiration amount	7,991								7,991
Lemon Inc
Summary Of Significant Accounting Policies [Line Items]
Deferred tax asset, noncurrent	8,706								8,706
Goodwill	29,914								29,914
Adjustment
Summary Of Significant Accounting Policies [Line Items]
Share-based compensation									(3,589)
Net income (loss)	(230)	1,039	620	575					2,004
Income tax (benefit) expense	1,482	39	167	(103)					1,585
Income tax benefit and deferred tax assets, net - noncurrent	(232)								(232)
Goodwill	3,222								3,222
Adjustment | Lemon Inc
Summary Of Significant Accounting Policies [Line Items]
Deferred tax asset, noncurrent	(3,222)								(3,222)
Goodwill	3,222								3,222
Share Based Compensation Award | Adjustment
Summary Of Significant Accounting Policies [Line Items]
Net income (loss)									2,236
Income tax (benefit) expense									$ 1,353