Quite frankly, I've never heard a thyroid referred to as "bulky", so the only thing I can think of that possibly there is inflammation causing that lobe to be swollen and inflamed looking. Perhaps it's indicative of a thyroiditis, but I can't say that for sure.
Isoechoic means the sound waves are equal to those of the surrounding tissue.
Is there a conclusion or "impression" at the end of the report? Those, typically, give an idea of what the radiologist recommends for follow-up...
Aside from that, do you have a diagnosed thyroid condition? If so, what condition?
What prompted the ultrasound?