Number of new stock issued during the period.

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Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Stockholders' Equity, Public Offering (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Aug. 12, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Stock issued, shares	741,750	742,000
Share price (in dollars per share)	$ 93.00
Net proceeds from public offering, net of discounts, commissions and other offering costs	$ 65,900	$ 65,879	$ 0	$ 0
Over-Allotment Option [Member]
Class of Stock [Line Items]
Stock issued, shares	96,750