Acquisitions - Pro Forma Information Operations as Acquisition of NTA (Details) - NTA - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Total revenues	$ 1,507,352	$ 1,339,896
Total expenses	1,259,213	1,288,690
Income before income taxes	248,139	51,206
Net income	$ 193,755	$ 43,373
Earnings Per Share, Pro Forma [Abstract]
Basic (in usd per share)	$ 4.64	$ 1.04
Diluted (in usd per share)	$ 4.62	$ 1.04

Business Combination, Pro Forma Expenses

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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Amount after tax of pro forma income from continuing operations as if the business combination had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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