Share Repurchase Program - Additional Information (Detail) - Share Repurchase Program [Member] - USD ($)	1 Months Ended	6 Months Ended	16 Months Ended
	Jan. 31, 2016	Jun. 30, 2017	Jun. 30, 2017	Oct. 31, 2016
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program authorized	$ 25,000,000
Shares repurchase program period	2 years
Commencement date		Mar. 01, 2016
Shares repurchase program additional authorized amount				$ 50,000,000
Total shares repurchased		127,894	283,762
Cost of common stock shares repurchased		$ 24,100,000
Amount available for repurchase		$ 27,000,000	$ 27,000,000