Condensed Statement of Operations (Detail) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net revenues	$ 247,868,092us-gaap_SalesRevenueNet	$ 163,771,833us-gaap_SalesRevenueNet	$ 86,695,506us-gaap_SalesRevenueNet
Operating cost and expenses
Compensation and benefits	119,610,072us-gaap_LaborAndRelatedExpense	73,043,620us-gaap_LaborAndRelatedExpense	42,374,929us-gaap_LaborAndRelatedExpense
Selling expenses	23,896,620us-gaap_SellingExpense	16,660,044us-gaap_SellingExpense	13,449,421us-gaap_SellingExpense
General and administrative expenses	24,611,880us-gaap_GeneralAndAdministrativeExpense	18,087,184us-gaap_GeneralAndAdministrativeExpense	8,901,330us-gaap_GeneralAndAdministrativeExpense
Total operating cost and expenses	158,188,130us-gaap_CostsAndExpenses	103,201,478us-gaap_CostsAndExpenses	60,850,473us-gaap_CostsAndExpenses
Loss from operations	89,679,962us-gaap_OperatingIncomeLoss	60,570,355us-gaap_OperatingIncomeLoss	25,845,033us-gaap_OperatingIncomeLoss
Other income (expenses):
Interest income	6,312,498us-gaap_InvestmentIncomeInterest	3,302,545us-gaap_InvestmentIncomeInterest	2,451,731us-gaap_InvestmentIncomeInterest
Investment income	3,821,469us-gaap_InvestmentIncomeNet	3,924,457us-gaap_InvestmentIncomeNet	3,044,856us-gaap_InvestmentIncomeNet
Other income (expenses)	(2,386,171)us-gaap_OtherNonoperatingIncomeExpense	3,423us-gaap_OtherNonoperatingIncomeExpense	110,690us-gaap_OtherNonoperatingIncomeExpense
Total other income	7,863,620us-gaap_NonoperatingIncomeExpense	7,539,142us-gaap_NonoperatingIncomeExpense	5,426,421us-gaap_NonoperatingIncomeExpense
(Loss) gain before taxes and income from equity in subsidiaries and VIEs	97,543,582	68,109,497	31,271,454
Income tax expenses	(24,531,504)us-gaap_IncomeTaxExpenseBenefit	(16,263,292)us-gaap_IncomeTaxExpenseBenefit	(8,979,649)us-gaap_IncomeTaxExpenseBenefit
Equity in profit of subsidiaries and VIEs	2,200,504	1,191,833	617,361
Net income attributable to Noah Holdings Limited shareholders	72,406,504us-gaap_NetIncomeLoss	51,435,171us-gaap_NetIncomeLoss	22,826,454us-gaap_NetIncomeLoss
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net revenues	0	0	0
Operating cost and expenses
Compensation and benefits	1,643,361		487,435
Selling expenses	27,217	24,281	15,995
General and administrative expenses	1,569,786	815,650	1,263,771
Total operating cost and expenses	3,240,364	839,931	1,767,201
Loss from operations	(3,240,364)	(839,931)	(1,767,201)
Other income (expenses):
Interest income	900,413	352,072	1,157,512
Investment income		107,019
Other income (expenses)	(73,235)	815,020	118,539
Total other income	827,178	1,274,111	1,276,051
(Loss) gain before taxes and income from equity in subsidiaries and VIEs	(2,413,186)	434,180	(491,150)
Income tax expenses	(205,810)	(232,692)	(222,265)
Equity in profit of subsidiaries and VIEs	75,025,500	51,233,683	23,539,869
Net income attributable to Noah Holdings Limited shareholders	$ 72,406,504	$ 51,435,171	$ 22,826,454

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