CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
REVENUES
Customer services	$ 330,909us-gaap_SalesRevenueServicesNet	$ 313,388us-gaap_SalesRevenueServicesNet
COSTS AND EXPENSES
Cost of services provided	168,043us-gaap_CostOfServices	161,308us-gaap_CostOfServices
Depreciation and amortization	10,781	10,214
Sales, general and administrative	105,575	100,832
Gain on sale of assets, net	(55)us-gaap_GainLossOnDispositionOfAssets1	(248)us-gaap_GainLossOnDispositionOfAssets1
Interest income, net	(47)us-gaap_InterestIncomeExpenseNet	(76)us-gaap_InterestIncomeExpenseNet
INCOME BEFORE INCOME TAXES	46,612	41,358
PROVISION FOR INCOME TAXES	16,331us-gaap_IncomeTaxExpenseBenefit	15,592us-gaap_IncomeTaxExpenseBenefit
NET INCOME	$ 30,281	$ 25,766
NET INCOME PER SHARE - BASIC AND DILUTED (in dollars per share)	$ 0.14us-gaap_EarningsPerShareBasicAndDiluted	$ 0.12us-gaap_EarningsPerShareBasicAndDiluted
DIVIDENDS PAID PER SHARE (in dollars per share)	$ 0.08	$ 0.07
Weighted average participating shares outstanding - basic and diluted (in shares)	218,541,000	218,986,000

Aggregate dividends paid during the period for each share of common stock outstanding.

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