Long-Term Incentive Plans (Stock Options Outstanding) (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-Term Incentive Plans [Abstract]
Number of shares, outstanding at beginning of year	2,325,300	2,548,000	3,715,406
Stock option awards exercised	2,050,000		(400,000)
Options expired or canceled	(37,500)	(222,700)	(767,406)
Number of shares, outstanding at end of year	237,800	2,325,300	2,548,000
Number of shares, exercisable at end of year	237,800	2,325,300	1,798,000
Outstanding at beginning of year, weighted average price per share	$ 6.3703	$ 10.9888	$ 20.6883
Exercised, weighted average price per share	4.4722	0	4.02
Expired or canceled, weighted average price per share	57.51	59.2118	61.5815
Outstanding at end of year, weighted average price per share	14.6689	6.3703	10.9888
Exercisable at end of year, weighted average price per share	$ 14.6689	$ 6.3703	$ 13.466