Receivables and Related Allowances - Schedule of Percent of Customers by State (Detail)	12 Months Ended
	Dec. 31, 2012
Arizona [Member]
Receivables And Related Allowances [Line Items]
Percent of customers by state	54.00%
Nevada [Member]
Receivables And Related Allowances [Line Items]
Percent of customers by state	36.00%
California [Member]
Receivables And Related Allowances [Line Items]
Percent of customers by state	10.00%