CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES
Net Income	$ 123,330	$ 111,332	$ 100,711
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	39,571	38,655	37,503
Pension Settlement		1,000
Provision for deferred income taxes	356	(1,870)	784
Stock based compensation expense	10,427	9,494	7,555
(Gain)/loss on sales/impairments of assets, net	(165)	(468)	405
Excess tax benefits from share-based payments	(3,722)	(3,231)	(2,367)
Provision for bad debts	10,388	11,095	8,879
Other, net	(102)	(113)	(762)
Changes in assets and liabilities:
Trade accounts receivables and other accounts receivables	(13,617)	(16,438)	(10,663)
Financed receivables	(950)	(1,453)	(1,855)
Materials and supplies	(118)	(655)	837
Other current assets	(4,613)	(1,469)	5,457
Other non-current assets	(1,343)	286	1,894
Accounts payable and accrued expenses	4,918	(2,175)	5,695
Unearned revenue	3,561	1,935	(59)
Accrued insurance	(1,572)	6,087	3,487
Accrued pension	(5,000)	(5,203)	(4,900)
Long-term accrued liabilities	1,316	(4,890)	2,046
Net cash provided by operating activities	162,665	141,919	154,647
INVESTING ACTIVITIES
Cash used for acquisitions of companies, net of cash acquired	(12,632)	(25,030)	(11,410)
Purchase of equipment and property	(18,632)	(19,040)	(18,652)
Cash from sales of franchises	102	322	149
Proceeds from sales of assets	372	1,055	759
Net cash used in investing activities	(30,790)	(42,693)	(29,154)
FINANCING ACTIVITIES
Payments on line of credit borrowings			(26,000)
Cash paid for common stock purchased	(13,723)	(19,938)	(30,215)
Dividends paid	(65,658)	(64,282)	(41,110)
Book overdrafts in bank accounts			(4,500)
Proceeds received upon exercise of stock options	6		69
Principal payments on capital lease obligations			(38)
Excess tax benefits from share-based payments	3,722	3,231	2,367
Net cash used in financing activities	(75,653)	(80,989)	(99,427)
Effect of exchange rate changes on cash	(3,088)	570	(704)
Net increase in cash and cash equivalents	53,134	18,807	25,362
Cash and cash equivalents at beginning of year	65,082	46,275	20,913
Cash and cash equivalents at end of year	118,216	65,082	46,275
Supplemental disclosure of cash flow information
Cash paid for interest			123
Cash paid for income taxes, net	69,354	62,998	51,983
Supplemental Disclosures of Non-Cash Items
Non-cash (increases) decreases in the minimum pension liability	45,700	(15,400)	(24,500)
Non-cash acquisition of assets in business combinations	$ 3,300	$ 3,000	$ 800