Stock-Based Compensation - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) plan $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Mar. 20, 2007 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of incentive plans | plan	2
Options, Granted (in shares) | shares	73,000
Weighted-average fair value of grants (in dollars per share) | $ / shares	$ 10.63
Outstanding at end of period, Weighted average remaining contractual term	4 years 1 month
Total fair value of options expensed before tax benefits	$ 0	$ 0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Granted (in shares) | shares	73,000	71,000	190,500
Weighted-average fair value of grants (in dollars per share) | $ / shares	$ 10.63	$ 12.62	$ 10.95
Option vesting term	4 years
Aggregate intrinsic value of stock options exercised	$ 2,300,000	$ 1,000,000	$ 2,600,000
Cash received from the exercise of options	3,100,000	2,300,000	8,800,000
Tax benefits realized for the tax deductions from options exercised	$ 900,000	400,000	1,000,000
Options vested (in shares) | shares	483,491
Weighted average exercise price (in dollars per share) | $ / shares	$ 20.08
Aggregate intrinsic value	$ 700,000
Outstanding at end of period, Weighted average remaining contractual term	4 years 1 month
Share-based compensation expense	$ 1,200,000	1,500,000	1,200,000
Unrecognized compensation cost related to stock option	$ 1,700,000
Weighted average period	2 years 2 months
Total fair value of options expensed before tax benefits	$ 1,300,000	1,300,000	1,100,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting term	3 years
Share-based compensation expense	$ 1,800,000	$ 1,300,000	$ 900,000
Weighted average period	1 year 9 months 18 days
Awards, Granted (in shares) | shares	108,500	86,300	65,550
Weighted average grant date fair value (in dollars per share) | $ / shares	$ 25.15	$ 24.74	$ 18.75
Vesting percentage in year one	33.00%
Vesting percentage in year two	33.00%
Vesting percentage in year three	34.00%
Compensation not yet recognized	$ 2,300,000
Fair value of awards vested in period	1,800,000	$ 1,300,000	$ 1,100,000
Tax benefit realized on vesting of options	700,000	500,000	400,000
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 500,000	$ 1,000,000	$ 300,000
Weighted average period	1 year 3 months 18 days
Awards, Granted (in shares) | shares	64,000	67,500	85,500
Weighted average grant date fair value (in dollars per share) | $ / shares	$ 25.51	$ 24.90	$ 16.15
Compensation not yet recognized	$ 1,400,000
Fair value of awards vested in period	900,000	$ 0	$ 0
Tax benefit realized on vesting of options	$ 300,000	$ 0	$ 0
2007 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance | shares	56,726			1,200,000
Shares reserved for future issuance other than stock options | shares				400,000
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance | shares	626,727			1,040,000