Face amount or stated value per share of common stock.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

Subsequent Events (Details) - $ / shares	Feb. 22, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Common Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01	$ 0.01
Subsequent Event
Subsequent Event [Line Items]
Merger Share Price	$ 40.00