INCOME TAXES - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Deferred tax asset valuation allowance	$ 257				$ 189						$ 257	$ 189
Income tax provision (benefit)	6,583	$ 6,066	$ 6,950	$ 7,124	3,130	[1]	$ 4,153	[2]	$ 7,280	$ 7,462	26,723	22,025	$ 25,316
Excess tax benefits recognized within income tax expense											500
Unrecognized tax benefits that if recognized would affect the annual effective tax rate	7,100				5,200						$ 7,100	5,200	2,600
Excess tax benefits relating to stock-based compensation												$ 590	$ 413
Tax Cuts And Jobs Act of 2017, incomplete accounting, change in tax rate, deferred tax asset, provisional income tax expense	$ 300
Internal Revenue Service (IRS)
Income Taxes [Line Items]
Tax examinations											2013
State income tax returns | Minimum
Income Taxes [Line Items]
Tax examination period											3 years
State income tax returns | Maximum
Income Taxes [Line Items]
Tax examination period											5 years
Earliest Tax Year | Domestic Production Activity
Income Taxes [Line Items]
Income tax provision (benefit)							1,500
2015 Tax Year | Domestic Production Activity
Income Taxes [Line Items]
Income tax provision (benefit)							$ 1,400
2014 Tax Year | Domestic Production Activity
Income Taxes [Line Items]
Income tax provision (benefit)					1,200
Tax Year 2013 | Domestic Production Activity
Income Taxes [Line Items]
Income tax provision (benefit)					$ 1,000

[1] The Company’s lower effective tax rate in the fourth quarter of 2016 (19%) was primarily attributable to the Company amending its 2014 and 2013 federal income tax returns to recognize favorable benefits related to the domestic production activities deduction, which increased basic and diluted earnings per share by approximately $0.03 during the quarter. (See Note 9)

[2] The Company’s lower effective tax rate in the third quarter of 2016 (20%) was primarily attributable to favorable benefits related to the domestic production activities deduction and federal research and development credit, which increased basic and diluted earnings per share by approximately $0.05 during the quarter. (See Note 9)