Basic and Diluted Weighted Average Shares Outstanding (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Weighted Average Number of Shares Outstanding [Line Items]
Weighted average common shares	34,097,805	33,649,296	33,995,323	33,336,989
Dilutive common stock options and restricted stock units	437,427	525,831	433,483	525,322
Dilutive effect of senior convertible notes	559,582		286,991
Weighted average common shares, assuming dilution	35,094,814	34,175,127	34,715,797	33,862,311