Exhibit 99.1



                     EXHIBIT 99.1 - JOINT FILING AGREEMENT



The  undersigned  hereby  agree  that  they  are  filing  this statement jointly
pursuant to Rule 13d-1(k)(1).  Each of them is responsible for the timely filing
of  such  Schedule  13G and any amendments thereto, and for the completeness and
accuracy  of  the information concerning such person contained therein; but none
of  them  is  responsible  for  the  completeness or accuracy of the information
concerning  the other persons making the filing, unless such person knows or has
reason  to  believe  that  such  information  is  inaccurate.

In  accordance  with  Rule  13d-1(k)(1)  promulgated  under  the  Securities and
Exchange  Act  of  1934,  as  amended, the undersigned hereby agree to the joint
filing with each other on behalf of each of them of such a statement on Schedule
13G and any amendments thereto with respect to the equity securities (as defined
in Rule 13d-1(i)) of the issuer, beneficially owned by each of them.  This Joint
Filing  Agreement  shall  be included as an exhibit to such Schedule 13G and any
amendments  thereto.


Date:  January 24, 2018

                                    First Trust Portfolios L.P.,
                                    First Trust Advisors L.P. and
                                    The Charger Corporation

				    By: /s/ James M. Dykas
    					---------------------------
				    Name:  James M. Dykas
				    Title: Chief Financial Officer of
       				           First Trust Portfolios L.P. and
       				           First Trust Advisors L.P., and
       			                   Chief Financial Officer and
       			                   Treasurer of The Charger
       			                   Corporation