Employee Termination Benefits (Details) - USD ($) shares in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Employee Termination Benefits
Cash		$ 18,637,000
Share-Based Compensation		$ 12,950,000
Number of Shares		763
Total Employee Termination Benefits	$ 0	$ 31,587,000
Executive Employee Termination Benefits
Employee Termination Benefits
Cash		11,945,000
Share-Based Compensation		$ 9,114,000
Number of Shares		554
Total Employee Termination Benefits		$ 21,059,000
Other Employee Termination Benefits
Employee Termination Benefits
Cash		6,692,000
Share-Based Compensation		$ 3,836,000
Number of Shares		209
Total Employee Termination Benefits		$ 10,528,000

Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

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