Summary of Significant Accounting Policies - Revenue - Contract Fulfillment Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Intake Costs asset
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Gross Carrying Amount	$ 41,224	$ 39,748
Accumulated Amortization	(23,579)	(24,504)
Net Carrying Amount	17,645	15,244
Commissions asset
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Gross Carrying Amount	68,008	58,424
Accumulated Amortization	(27,178)	(34,637)
Net Carrying Amount	$ 40,830	$ 23,787

Amount, before allowance for credit loss, of right to consideration in exchange for good or service transferred to customer, when right is conditioned on something other than passage of time.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130533-203044

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