Significant Non-Cash Investing and Financing Activities (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Cash Flow, Supplemental [Line Items]
Other payable issued for purchased customer accounts	$ 25,439
Notes payable issued or assumed for purchased customer accounts	59	1,603	3,821
Estimated acquisition earn-out payables and related charges	21,479	30,525	25,090
Notes received on the sale of fixed assets and customer accounts	$ 967	$ 8,166	$ 1,825