Condensed, Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 43,460,000	$ 35,778,000	$ 75,283,000	$ 72,099,000
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustment	(3,597,000)	(1,477,000)	(6,341,000)	(413,000)
Other Comprehensive Income (Loss), Net of Tax	(3,597,000)	(1,477,000)	(6,341,000)	(413,000)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	39,863,000	34,301,000	68,942,000	71,686,000
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	1,798,000	1,458,000	3,136,000	2,534,000
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	38,065,000	32,843,000	65,806,000	69,152,000
Comprehensive Income Attributable To Redeemable Noncontrolling Interests	$ 1,900,000	$ 1,300,000