CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
REVENUES
Customer services	$ 1,270,909	$ 1,205,064	$ 1,136,890
COSTS AND EXPENSES
Cost of services provided	647,578	616,842	583,089
Depreciation and amortization	38,655	37,503	36,408
Sales, general and administrative	407,488	388,710	373,288
(Gain)/loss on sales/impairment of assets, net	(468)	405	123
Pension settlement loss	1,000
Interest expense	14	508	437
TOTAL COSTS AND EXPENSES	1,094,267	1,043,968	993,345
INCOME BEFORE INCOME TAXES	176,642	161,096	143,545
PROVISION FOR INCOME TAXES
Current	67,180	59,601	51,468
Deferred	(1,870)	784	2,075
TOTAL PROVISION FOR INCOME TAXES	65,310	60,385	53,543
NET INCOME	$ 111,332	$ 100,711	$ 90,002
INCOME PER SHARE - BASIC (in dollars per share)	$ 0.76	$ 0.69	$ 0.61
INCOME PER SHARE - DILUTED (in dollars per share)	$ 0.76	$ 0.69	$ 0.61
Weighted average shares outstanding - basic (in shares)	146,299	146,882	148,030
Weighted average shares outstanding - diluted (in shares)	146,306	146,946	148,231
DIVIDENDS PAID PER SHARE (in dollars per share)	$ 0.44	$ 0.28	$ 0.24