Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
REVENUE	$ 2,280,259	$ 2,218,594	$ 2,120,972
COST OF SERVICES	970,693	943,331	894,628
SELLING, GENERAL AND ADMINISTRATIVE EXPENSES	853,116	813,856	775,050
OPERATING INCOME	456,450	461,407	451,294
OTHER INCOME (EXPENSE):
Interest income	205	268	282
Interest expense	(154,273)	(188,102)	(232,935)
Debt call premium and accelerated amortization of deferred financing costs	(2,304)	(73,309)	(23,105)
Other, net	(1,405)	7,026	2,206
Other expense	(157,777)	(254,117)	(253,552)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE	298,673	207,290	197,742
INCOME TAX EXPENSE ATTRIBUTED TO CONTINUING OPERATIONS	107,757	72,679	74,651
INCOME FROM CONTINUING OPERATIONS	190,916	134,611	123,091
INCOME FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES	50,924	23,794	20,111
NET INCOME	$ 241,840	$ 158,405	$ 143,202
EARNINGS PER COMMON SHARE-BASIC:
Continuing Operations	$ 2.29	$ 1.60	$ 1.56
Discontinued Operations	0.61	0.29	0.26
Total Earnings Per Common Share-Basic	2.90	1.89	1.82
EARNINGS PER COMMON SHARE-DILUTED
Continuing Operations	2.24	1.57	1.53
Discontinued Operations	0.59	0.28	0.25
Total Earnings Per Common Share-Diluted	$ 2.83	$ 1.85	$ 1.78
WEIGHTED AVERAGE NUMBER OF SHARES OUTSTANDING:
Basic Common	83,420	84,007	78,875
Diluted Common	85,394	85,507	80,318