Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109237824&loc=d3e1703-114919

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921

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

Benefit Plans - Contributions to Pension and Other Postretirement Benefit Plans (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Jul. 01, 2019
Qualified Plan (ERP)
Benefit Plans
Benefit accruals for the company's employees	$ 0
Pension Benefits
Benefit Plans
Benefit accruals for the company's employees	(104,597)	$ (100,626)
Pension Benefits \| Qualified Plan (ERP)
Benefit Plans
Expected contributions in 2021	0
Pension Benefits \| Nonqualified Plan
Benefit Plans
Expected contributions in 2021	200
SERP and Directors' Plan
Benefit Plans
Benefit accruals for the company's employees			$ 0
Expected contributions in 2021	0
Other Benefits \| Nonqualified Plan
Benefit Plans
Expected contributions in 2021	$ 1,200