Stock-based Compensation - Additional Information (Detail) - shares	1 Months Ended	9 Months Ended
	Apr. 30, 2015	Sep. 30, 2015
2012
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Target number of shares		192,000
Performance Units Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance period		3 years
Award description		Generally, the recipients will receive a target number of shares if the Company’s total shareholder return is positive and, when compared to the peer group, is at the 50th percentile and two times the target if at the 75th percentile or higher.
Performance Units Awards | 2012
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	384,000