Quarterly report pursuant to Section 13 or 15(d)

Unaudited Consolidated Statements of Stockholders' Equity (Parenthetical)

v3.20.2
Unaudited Consolidated Statements of Stockholders' Equity (Parenthetical)
12 Months Ended
Dec. 31, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]  
Accounting Standards Update [Extensible List] us-gaap:AccountingStandardsUpdate201602Member