Organization - Additional Information (Detail)	1 Months Ended	9 Months Ended
	Mar. 31, 2015 USD ($) $ / shares shares	Sep. 30, 2015 Segment
Organization And Nature Of Business [Line Items]
Number of operating segment | Segment		1
Follow on offering price per share | $ / shares	$ 40.00
Proceeds from offering and over-allotment option, net	$ 108,400,000
Follow-on Offering
Organization And Nature Of Business [Line Items]
Stock issued during the period | shares	2,870,000
Underwriting discounts, commissions and offering expenses, net	$ 358,000
Underwriters Overallotment Option
Organization And Nature Of Business [Line Items]
Stock issued during the period | shares	374,348