Valuation and Qualifying Accounts (Details) - Valuation Allowance for deferred tax assets - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 947
Amount Charged to Expense	730	$ 947
Balance at End of Period	$ 1,677	$ 947

Amount of increase in valuation and qualifying accounts and reserves from charge to cost and expense.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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