Goodwill and Identifiable Assets Acquired Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Intangible assets subject to amortization:
Gross Carrying Amount	$ 305,359	$ 296,586
Accumulated Amortization	198,535	164,373
Net Carrying Amount	106,824	132,213
Intangible assets not subject to amortization:
Trademarks, Carrying Amount	245,942	245,517
Goodwill	894,095	873,513
Total
Gross Carrying Amount	551,301	542,103
Net Carrying Amount	352,766	377,730
Customer Relationships [Member]
Intangible assets subject to amortization:
Gross Carrying Amount	202,588	196,204
Accumulated Amortization	119,272	98,804
Net Carrying Amount	$ 83,316	97,400
Customer Relationships [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	2 months
Customer Relationships [Member] | Maximum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	10 years
Contractor Relations [Member]
Intangible assets subject to amortization:
Gross Carrying Amount	$ 71,121	69,721
Accumulated Amortization	59,174	50,528
Net Carrying Amount	$ 11,947	19,193
Contractor Relations [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	2 years
Contractor Relations [Member] | Maximum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	5 years
Noncompete Agreements [Member]
Intangible assets subject to amortization:
Gross Carrying Amount	$ 11,850	10,861
Accumulated Amortization	6,600	4,922
Net Carrying Amount	$ 5,250	5,939
Noncompete Agreements [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	2 years
Noncompete Agreements [Member] | Maximum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	7 years
Computer Software, Intangible Asset [Member]
Intangible Assets [Line Items]
Estimated Useful Life	6 years
Intangible assets subject to amortization:
Gross Carrying Amount	$ 18,900	18,900
Accumulated Amortization	12,816	9,666
Net Carrying Amount	$ 6,084	9,234
Contract-Based Intangible Assets [Member]
Intangible Assets [Line Items]
Estimated Useful Life	5 years
Intangible assets subject to amortization:
Gross Carrying Amount	$ 900	900
Accumulated Amortization	673	453
Net Carrying Amount	$ 227	$ 447