Stock Based Compensation - Company's Stock Options Outstanding and Stock Options Vested and Exercisable (Detail)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding (in shares) | shares	1,210,141
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 16.31
Options Vested and Exercisable (in shares) | shares	1,135,278
Options Vested and Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 15.75
$8.00 to $15.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower range limit (in dollars per share)	8.00
Range of Exercise Prices, upper range limit (in dollars per share)	$ 15.00
Options Outstanding (in shares) | shares	546,543
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 10.06
Options Vested and Exercisable (in shares) | shares	546,543
Options Vested and Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 10.06
$15.01 to $21.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower range limit (in dollars per share)	15.01
Range of Exercise Prices, upper range limit (in dollars per share)	$ 21.00
Options Outstanding (in shares) | shares	322,661
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 18.33
Options Vested and Exercisable (in shares) | shares	322,661
Options Vested and Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 18.33
$21.01 to $28.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower range limit (in dollars per share)	21.01
Range of Exercise Prices, upper range limit (in dollars per share)	$ 28.00
Options Outstanding (in shares) | shares	340,937
Options Outstanding, Weighted-Average Exercise Price (in dollars per share)	$ 24.41
Options Vested and Exercisable (in shares) | shares	266,074
Options Vested and Exercisable, Weighted-Average Exercise Price (in dollars per share)	$ 24.30