Lines of Credit - Stand-by Letters of Credit Outstanding (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Standby Letters of Credit
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount	$ 9.2	$ 8.8

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.

No definition available.

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration