Recent Accounting Pronouncements - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock-based compensation expense	$ 3,184,000	$ 3,391,000
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock-based compensation expense	200,000
Minimum [Member] | Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Anticipated increase in assets and liabilities	80,000,000
Maximum [Member] | Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Anticipated increase in assets and liabilities	$ 100,000,000