Pulling Information About Stored Procedures Query

I am trying to pull information about all the user created stored procedures in a database with a query. I have successfully pulled all the procs with parameters, but I want to result set to also contain the stored procedures without parameters. I can't quite get it. Any help would be appreciated:

SELECT procs.name as ProcName,
params.name as ParameterName,
types.name as ParamType,
params.max_length,
params.precision,
params.scale,
params.is_output
FROM sys.procedures procs
LEFT OUTER JOIN sys.all_parameters params
ON procs.object_id = params.object_id
LEFT OUTER JOIN sys.types types
ON params.system_type_id = types.system_type_id

WHERE params.user_type_id = types.user_type_id
AND procs.is_ms_shipped = 0
ORDER BY procname,
params.parameter_id