Issued and Outstanding Stock Options (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Long-Term Stock Incentive Plans:
Options outstanding at the beginning of period	3,581,752	5,618,686
Granted	0	0
Exercised	0	(166,375)	(603,000)
Forfeited	(1,016,667)	(1,513,934)
Expired	(305,750)	(356,625)
Options outstanding at the end of period	2,259,335	3,581,752	5,618,686
Options exercisable at the end of the period	2,259,335	3,581,752
Options outstanding at the beginning of year, weighted average exercise price	$ 15.44	$ 15.74
Granted	$ 0	$ 0
Exercised		$ 13.25
Forfeited	$ 15.07	$ 16.22
Expired	$ 17.34	$ 17.91
Options outstanding at the end of year, weighted average exercise price	$ 15.35	$ 15.44	$ 15.74
Options exercisable at the end of the year, exercise price	$ 15.35	$ 15.44