Summary of Business and Significant Accounting Policies - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Mar. 31, 2014	Apr. 30, 2014
Subsidiary, Sale of Stock [Line Items]
Offering costs not yet paid		$ 515,000
Class A common stock [Member]
Subsidiary, Sale of Stock [Line Items]
Shares issued in follow-on offering	13,800,000
Shares sold to underwriters under over-allotment option	1,800,000
Shares sold and issued by the Company	1,390,000
Shares sold by certain selling shareholders	12,410,000
Offering price per share	$ 26.35
Net proceeds from initial public offering, after deducting underwriting discounts and commissions	35,300,000	35,000,000
Estimated offering costs	800,000
Offering costs not yet paid		$ 500,000