Stock Options and Stock-Based Employee Compensation - Summary of All Stock Option Transactions (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward
Shares, Outstanding, Beginning Balance	1,021,314	1,960,279	1,774,552
Shares, Granted at market price	0	30,750	373,187
Shares, Cancelled or expired	(7,480)	(37,412)	(63,700)
Shares, Exercised	(90,011)	(932,303)	(123,760)
Shares, Outstanding Ending Balance	923,823	1,021,314	1,960,279
Shares, Options Exercisable	817,573
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 3.11	$ 3.78	$ 3.65
Weighted Average Exercise Price, Granted at market price	0.00	4.96	3.70
Weighted Average Exercise Price, Cancelled or expired	4.04	4.71	3.95
Weighted Average Exercise Price, Exercised	1.83	4.51	1.66
Weighted Average Exercise Price, Outstanding, Ending Balance	3.23	$ 3.11	$ 3.78
Weighted Average Exercise Price, Options Exercisable	$ 3.16
Weighted Average Remaining Contractual Term, Outstanding	4 years 9 months 3 days
Weighted Average Remaining Contractual Term, Options exercisable	4 years 5 months 4 days