Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities - Significant Non-Cash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Elements [Abstract]
Change in Cash and Cash Equivalents due to reclass from Restricted Cash	$ 33,000	$ 32,200
Cash paid during the period for:
Interest	37,542	25,115	$ 16,501
Income taxes	132,874	118,290	110,190
Significant non-cash investing and financing activities
Other payables issued for purchased customer accounts	10,029	1,930	1,425
Estimated acquisition earn-out payables and related charges	36,899	33,229	5,091
Notes received on the sale of fixed assets and customer accounts	$ 7,755	$ 6,340	$ 1,108