BUTTE, Mont. and SIOUX FALLS, S.D., Feb. 12, 2020 /PRNewswire/ -- NorthWestern Corporation d/b/a NorthWestern Energy (NYSE: NWE) reported financial results for the year ended December 31, 2019. Net income for the period was $202.1 million, or $3.98 per diluted share, as compared with net...