Acquisitions (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Aug. 31, 2016	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 01, 2016
Acquisition
Purchase price paid in cash			$ 123,351	$ 45,000	$ 1,669,449
Amortization of Intangible Assets			28,765	$ 24,180	$ 26,490
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months			29,068
Finite-Lived Intangible Assets, Amortization Expense, Year Two			26,434
Finite-Lived Intangible Assets, Amortization Expense, Year Three			24,330
Finite-Lived Intangible Assets, Amortization Expense, Year Four			22,204
Finite-Lived Intangible Assets, Amortization Expense, Year Five			20,415
Finite-Lived Intangible Assets, Amortization Expense, after Year Five			$ 161,526
Other Intangible Assets [Member]
Acquisition
Expected Life			3 years
Vulcan
Acquisition
Business Acquisition, Percentage of Voting Interests Acquired						100.00%
Purchase price paid in cash	$ 113,000
Intangible assets	32,930
Amortization of Intangible Assets			$ 872
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months			2,652
Finite-Lived Intangible Assets, Amortization Expense, Year Two			2,552
Finite-Lived Intangible Assets, Amortization Expense, Year Three			2,081
Finite-Lived Intangible Assets, Amortization Expense, Year Four			1,742
Finite-Lived Intangible Assets, Amortization Expense, Year Five			1,642
Finite-Lived Intangible Assets, Amortization Expense, after Year Five			$ 21,400
Vulcan | Customer and scrap generator relationships
Acquisition
Intangible assets	25,600
Expected Life			20 years
Vulcan | Trade names
Acquisition
Intangible assets	6,100
Expected Life			25 years
Vulcan | Other Intangible Assets [Member]
Acquisition
Intangible assets	$ 1,200
Consolidated Systems, Inc [Member]
Acquisition
Purchase price paid in cash		$ 45,000
Working capital purchased		$ 30,000