Goodwill and Identifiable Assets (Acquired Intangible Assets) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Apr. 02, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Intangible Assets [Line Items]
Amortization of intangible assets		$ 18,548	$ 8,299	$ 26,149	$ 16,763
Intangible assets subject to amortization:
Gross Carrying Amount		483,528		483,528		$ 305,359
Accumulated Amortization		224,621		224,621		198,535
Net Carrying Amount		258,907		258,907		106,824
Intangible assets not subject to amortization:
Trademarks, Carrying Amount		262,291		262,291		245,942
Goodwill, Carrying Amount	$ 526,565	1,420,012		1,420,012		894,095
Intangible Assets, Gross (Excluding Goodwill)		745,819		745,819		551,301
Total
Intangible Assets, Net (Excluding Goodwill)		521,198		521,198		352,766
Customer Contractual Relationships
Intangible Assets [Line Items]
Estimated Useful Life	13 years
Intangible assets subject to amortization:
Gross Carrying Amount		343,762		343,762		202,588
Accumulated Amortization		129,680		129,680		119,272
Net Carrying Amount		214,082		$ 214,082		83,316
Customer Contractual Relationships | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life				2 years
Customer Contractual Relationships | Maximum [Member]
Intangible Assets [Line Items]
Estimated Useful Life				13 years
Contractor Relations [Member]
Intangible assets subject to amortization:
Gross Carrying Amount		71,130		$ 71,130		71,121
Accumulated Amortization		63,123		63,123		59,174
Net Carrying Amount		8,007		$ 8,007		11,947
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
Order or Production Backlog [Member]
Intangible Assets [Line Items]
Estimated Useful Life	1 year
Intangible assets subject to amortization:
Gross Carrying Amount		26,100		$ 26,100		0
Accumulated Amortization		8,700		8,700		0
Net Carrying Amount		17,400		$ 17,400		0
Order or Production Backlog [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life				1 year
Non-compete agreements
Intangible assets subject to amortization:
Gross Carrying Amount		22,236		$ 22,236		11,850
Accumulated Amortization		7,972		7,972		6,600
Net Carrying Amount		14,264		$ 14,264		5,250
Non-compete agreements | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	4 years			2 years
Non-compete agreements | Maximum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	7 years			7 years
Contract-Based Intangible Assets [Member]
Intangible Assets [Line Items]
Estimated Useful Life	5 years
Intangible assets subject to amortization:
Gross Carrying Amount		1,400		$ 1,400		900
Accumulated Amortization		755		755		673
Net Carrying Amount		645		$ 645		227
Contract-Based Intangible Assets [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life				5 years
Computer Software, Intangible Asset [Member]
Intangible assets subject to amortization:
Gross Carrying Amount		18,900		$ 18,900		18,900
Accumulated Amortization		14,391		14,391		12,816
Net Carrying Amount		$ 4,509		$ 4,509		$ 6,084
Computer Software, Intangible Asset [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life				6 years