Concatenate Expression with If Statement (Report Builder)

Hello There!

I'm somewhat of a plebe when it comes to paginated reports so hoping to get some help. 

Using the period table in the column group filtered to yesterday, month to date, year to date I get all the measures in the columns I need. What I'm trying to do is add the dates affiliated with each period to match the report mockup. 

The dataset is already filtered so that it includes only the periods yesterday, month to date and year to date, the 3 values in the column group. 

I imagine the expression would look something like this:

=Fields!Period.Value & IF(Count(Fields!Fields!Period_Date.Value >1), Min(Fields!Period_Date.Value & "-" & Max(Fields!Period_Date.Value, Fields!Period_Date.Value))

But my syntax is causing an error and I'm not entirely sure why. 

In other words, if there is more than one date associatd with the period value then show the min and max date to the right of the period value, otherwise if there is only 1 value (yesterday) then display that date. 

I'm not really worried about the values in the rows. For this request I'm just looking for something that will dynamically display the period name (yesterday, current month to date, year to date) with the corresponding date(s) associated with the period in the column grouping, to match the mockup. 

Link to Supporting Doc 

Mockup

 ReportBuilderDesignerPageReport Builder Output Page