Employee Benefits (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Defined Contribution Plan, Employer Matching Contribution, Percent	4.00%
Defined Contribution Plan Employer Matching Contribution Amount	$ 6,800
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent	1.00%
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Amount	2,500
Defined Benefit Plan, Net Periodic Benefit Cost	2,600,000	[1]	2,705,000	[1]	2,430,000	[1]
Deferred Compensation Plan Assets	27,800,000		25,100,000
Deferred Compensation Liability, Classified, Noncurrent	31,300,000		28,100,000
Deferred Compensation Arrangement with Individual, Compensation Expense	400,000		300,000		0
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	500,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	2,000,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	800,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	900,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	1,200,000
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	7,000,000
Defined Benefit Plan, Contributions by Employer	6,400,000
Defined Benefit Plan, Benefits Paid	680,000	[2]	390,000	[2]	220,000	[2]
Defined Benefit Plan, Actual Return on Plan Assets	0
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	3.60%
Weighted Average Amortization Period	14 years
Defined Benefit Plan Amortization of Unrecognized Gains Losses	200,000		100,000		200,000
Saving and Investment Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost	14,200,000		15,900,000		14,600,000
Pension Reinsurance Asset [Member]
Other Assets	$ 8,800,000

[1] Pension expense is classified in SG&A in the Consolidated Statements of Operations.

[2] The Company projects the following amounts will be paid in future years to plan participants: $0.5 million in 2013; $2.0 million in 2014; $0.8 million in 2015; $0.9 million in 2016; $1.2 million in 2017; and $7.0 million in the five years thereafter.