Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Intangible Assets, by category
Gross Carrying Amount	$ 427,081		$ 427,081		$ 170,588
Accumulated Amortization	100,393		100,393		101,381
Amortization expense for intangible assets	1,901	$ 1,197	3,840	$ 2,027
Estimated amortization expense for next 5 years
2019	18,700		18,700
2020	29,500		29,500
2021	26,250		26,250
2022	23,000		23,000
2023	23,000		23,000
Customer related
Intangible Assets, by category
Gross Carrying Amount	154,835		154,835		122,379
Accumulated Amortization	94,593		94,593		93,580
Permits and rights
Intangible Assets, by category
Gross Carrying Amount	176,121		176,121		0
Accumulated Amortization	0		0		0
Patents
Intangible Assets, by category
Gross Carrying Amount	262		262		2,598
Accumulated Amortization	171		171		2,503
Technology related
Intangible Assets, by category
Gross Carrying Amount	34,920		34,920		35,831
Accumulated Amortization	3,690		3,690		2,681
Trade names
Intangible Assets, by category
Gross Carrying Amount	31,542		31,542		5,565
Accumulated Amortization	858		858		681
Air rights
Intangible Assets, by category
Gross Carrying Amount	25,584		25,584		0
Accumulated Amortization	0		0
Other
Intangible Assets, by category
Gross Carrying Amount	3,817		3,817		4,215
Accumulated Amortization	$ 1,081		$ 1,081		$ 1,936