Commitments and Contingencies - Fiduciary Funds (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($)
Fiduciary and pools’ underwriting accounts
Assets held on behalf of unaffiliated pool members	$ 10,522	$ 11,501
Escrow bond arrangements	1,014	951
Total	11,536	$ 12,452
Unfunded commitments related to a limited partnership and a fixed income security	$ 163,700
Number of unaffiliated pool members \| item	2

The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 6A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=SL6742756-110258

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant