In my gathering of Detert data, I came up with the following for your family:
Johann Detert b. c1836 in Pommern, d. Pommern sons: August b. 7 Mar 1856 Stettin, Pommern m. bef 1881 Auguste Lowe d. 11 Mar 1920 Carver Co., MN William b. June 1857 Stettin, Pommern Immigrated to US in 1884 m. abt 1890 Matilde Ottilie Erdmann d. aft 1920 Pierce Co., WI Carl b. 1861 Stettin, Pommern m. 28 Nov 1895 Johanna Radtke d. betw 1908-1910 Kenosha County, WI
There is not an immediate relationship to my Detert Family what settled in Martin Co., MN, but the fact the family was from Stettin is very close to where our family lived in Pommern.