Lessor Leases Sales-type Lease Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Leases [Abstract]
Sales-type lease revenues	$ 11,507	$ 9,857
Interest income on sales-type lease receivables	$ 409	$ 267

Amount of interest income from net investment in sales-type lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 5
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919372-209981

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 50
-Paragraph 6A
-URI http://asc.fasb.org/extlink&oid=109225645&loc=SL77927221-108306

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 25
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82918700&loc=SL77919101-209958

Name:	us-gaap_SalesTypeLeaseInterestIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration