Restructuring - Schedule of Pre-tax Restructuring Costs (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring charges	$ 3,907	$ 3,498	$ 3,907	$ 3,498
Severance, benefits and outplacement costs
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring charges	1,109	3,183	1,109	3,183
Contract termination costs
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring charges	2,798	185	2,798	185
Vacated leased office space
Restructuring Cost and Reserve [Line Items]
Pre-tax restructuring charges	$ 0	$ 130	$ 0	$ 130

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to 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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration