Summary of Status of Two Thousand Four Incentive Plan (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Shares
Outstanding at beginning of year	2,934		2,335		1,745
Stock Options	75		30		37
SARs	602	[1]	622	[1]	592	[1]
Forfeited	(48)		(53)		(39)
Outstanding at end of year	3,563		2,934		2,335
Options and SARs exercisable at end of year	1,592		1,086		621
Weighted average exercise price
Outstanding at beginning of year	$ 32.40		$ 34.35		$ 36.08
Stock Options	$ 19.01		$ 19.10		$ 28.39
SARs	$ 20.13	[1]	$ 25.65	[1]	$ 29.95	[1]
Forfeited	$ 28.92		$ 31.69		$ 38.96
Outstanding at end of year	$ 30.09		$ 32.40		$ 34.35
Options and SARs exercisable at end of year	$ 36.61		$ 37.46		$ 37.65
Weighted-average fair value of options and SARs granted during the year	$ 7.25		$ 9.69		$ 12.51

[1] Upon exercise, SARs entitle the recipient to receive shares of common stock equal to the increase in value of the award between the grant date and the exercise date.