Segment Information Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Number of Reportable Segments	3
Revenues	$ 2,432,854	$ 2,260,863
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	57,472	49,213
Income Tax Expense (Benefit)	(21,657)	(17,910)
Net Income (Loss) Attributable to Parent	35,815	31,303
Assets	4,098,467		4,141,492
U.S. [Member]
Segment Reporting Information [Line Items]
Revenues	1,998,500	1,834,626
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	53,156	45,862
Income Tax Expense (Benefit)	(20,361)	(16,828)
Net Income (Loss) Attributable to Parent	32,795	29,034
Assets	3,516,075		3,529,643
U.K. [Member]
Segment Reporting Information [Line Items]
Revenues	299,541	247,701
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	5,121	4,617
Income Tax Expense (Benefit)	(999)	(965)
Net Income (Loss) Attributable to Parent	4,122	3,652
Assets	359,588		327,644
Brazil [Member]
Segment Reporting Information [Line Items]
Revenues	134,813	178,536
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	(805)	(1,266)
Income Tax Expense (Benefit)	(297)	(117)
Net Income (Loss) Attributable to Parent	(1,102)	(1,383)
Assets	$ 222,804		$ 284,205