Reconciliation Between Statutory Federal Income Tax Rate and Effective Income Tax Rate as Percentage of Income (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Effective Tax Rate Reconciliation [Line Items]
Statutory rate	35.00%	35.00%	35.00%
Increase (decrease) in rate resulting from:
State taxes	4.70%	4.10%	4.30%
Domestic manufacturer's deduction	(2.70%)	(2.80%)	(2.40%)
Other	0.40%	0.10%	0.10%
Effective rate	37.40%	36.40%	37.00%