Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Intangible Assets, by category
Gross Carrying Amount	$ 411,845		$ 412,657
Accumulated Amortization	117,125		113,575
Amortization expense for intangible assets	5,918	$ 1,939
Estimated amortization expense for next 5 years
2020	24,300
2021	23,100
2022	22,400
2023	22,400
2024	22,400
Customer related
Intangible Assets, by category
Gross Carrying Amount	143,092		143,996
Accumulated Amortization	99,280		99,327
Permits
Intangible Assets, by category
Gross Carrying Amount	170,448		170,322
Accumulated Amortization	7,045		4,694
Patents
Intangible Assets, by category
Gross Carrying Amount	192		249
Accumulated Amortization	132		168
Technology related
Intangible Assets, by category
Gross Carrying Amount	36,739		36,467
Accumulated Amortization	6,142		5,635
Trade names
Intangible Assets, by category
Gross Carrying Amount	31,558		31,719
Accumulated Amortization	2,801		2,182
Air rights
Intangible Assets, by category
Gross Carrying Amount	26,139		26,139
Accumulated Amortization	549		411
Other
Intangible Assets, by category
Gross Carrying Amount	3,677		3,765
Accumulated Amortization	$ 1,176		$ 1,158

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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