Nominal or face amount used to calculate payment on derivative.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

Derivatives - Interest Rate Risk (Details) - Derivatives designated as hedging instruments - USD ($) $ in Millions	Dec. 31, 2019	Aug. 31, 2017
Interest rate swaps
Notional Disclosures
Notional amount of interest rate swaps	$ 400.0
May 2020
Notional Disclosures
Notional amount of interest rate swaps	100.0
March 2022
Notional Disclosures
Notional amount of interest rate swaps	$ 300.0	$ 300.0