CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
REVENUES
Customer services	$ 1,337,374	$ 1,270,909	$ 1,205,064
COSTS AND EXPENSES
Cost of services provided	678,459	647,578	616,842
Depreciation and amortization	39,571	38,655	37,503
Sales, general and administrative	428,288	407,488	388,710
(Gain)/loss on sales/impairment of assets, net	(165)	(468)	405
Pension settlement loss		1,000
Interest (income)/expense	(385)	14	508
TOTAL COSTS AND EXPENSES	1,145,768	1,094,267	1,043,968
INCOME BEFORE INCOME TAXES	191,606	176,642	161,096
PROVISION FOR INCOME TAXES
Current	67,920	67,180	59,601
Deferred	356	(1,870)	784
TOTAL PROVISION FOR INCOME TAXES	68,276	65,310	60,385
NET INCOME	$ 123,330	$ 111,332	$ 100,711
INCOME PER SHARE - BASIC (in dollars per share)	$ 0.84	$ 0.76	$ 0.69
INCOME PER SHARE - DILUTED (in dollars per share)	$ 0.84	$ 0.76	$ 0.69
Weighted average shares outstanding - basic (in shares)	146,081	146,299	146,882
Weighted average shares outstanding - diluted (in shares)	146,081	146,299	146,882
DIVIDENDS PAID PER SHARE (in dollars per share)	$ 0.45	$ 0.44	$ 0.28