Find Date gap between SQL rows

DECLARE @Table TABLE

(

       Id                   INT IDENTITY(1,1),

       Idn                  INT,

       StartDate            DATE,

       EndDate              DATE

) 

INSERT INTO @Table

SELECT 1,'2013-07-01', '2014-06-30'

UNION

SELECT 1,'2014-07-01', '2015-06-30'

UNION

SELECT 1,'2015-07-10', '2016-06-30'

UNION

SELECT 1,'2016-07-05', '2017-06-30'

Select * From @Table

 

;WITH CTE AS

(

       SELECT *, ROW_NUMBER() OVER(PARTITION BY Idn ORDER BY StartDate) rownumber

       FROM   @Table

)

SELECT A.Id, A.Idn, A.StartDate, A.EndDate, B.StartDate AS NextStartDate, DATEDIFF(D, A.EndDate, B.StartDate)  AS Gap

FROM   CTE AS A JOIN CTE AS B ON B.Idn = A.Idn AND B.RowNumber = A.RowNumber + 1

WHERE  DATEDIFF(D, A.EndDate, B.StartDate) > 1