Stock Plans and Other Incentives - Summary of Options (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding	530,000	547,500	582,500	627,724
Remaining Contractual Life (Years)	2 years	3 years
Weighted Average Exercise Price	$ 9.64	$ 9.61	$ 9.52	$ 9.05
Intrinsic Value	$ 6,681,475	$ 7,728,150
Exercise Price Range $7.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices	$ 7.50
Outstanding	10,000	20,000
Remaining Contractual Life (Years)	6 months	1 year 7 months 6 days
Weighted Average Exercise Price	$ 7.50	$ 7.50
Intrinsic Value	$ 147,500	$ 324,600
Exercise Price Range $8.03 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices	$ 8.03
Outstanding	225,000	225,000
Remaining Contractual Life (Years)	3 years 6 months	4 years 7 months 6 days
Weighted Average Exercise Price	$ 8.03	$ 8.03
Intrinsic Value	$ 3,200,625	$ 3,533,625
Exercise Price Range $10.40 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices	$ 10.40
Outstanding	275,000	282,500
Remaining Contractual Life (Years)	4 months 24 days	1 year 4 months 24 days
Weighted Average Exercise Price	$ 10.40	$ 10.40
Intrinsic Value	$ 3,258,750	$ 3,765,725
Exercise Price Range $18.52 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices	$ 18.52
Outstanding	20,000	20,000
Remaining Contractual Life (Years)	7 years 4 months 24 days	8 years 4 months 24 days
Weighted Average Exercise Price	$ 18.52	$ 18.52
Intrinsic Value	$ 74,600	$ 104,200