Savings and Profit Sharing Plans - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2012
Savings And Profit Sharing Plans [Line Items]
Qualified employees participation contribution, percentage of gross earnings	15.00%
100% Matching Contribution [Member]
Savings And Profit Sharing Plans [Line Items]
Matching contribution rate by the employer	100.00%
Percentage of gross eligible earnings for matching contribution	2.00%
50% Matching Contribution [Member]
Savings And Profit Sharing Plans [Line Items]
Matching contribution rate by the employer	50.00%
Percentage of gross eligible earnings for matching contribution	4.00%