The massive multi-user multiple-input multiple-output (MU-MIMO) can be adapted to meet the increasing requirement of data throughput services in wireless transmission systems. The combination of the Single Carrier Frequency Division Multiple Access (SC-FDMA) with the massive MU-MIMO technology can be employed for the uplink transmission to meet the requirement of data rates and error performance. In this paper, for practical implementation, we integrate multi-user detection, Kalman channel estimation and turbo equalization and propose turbo detectors to solve the problem of huge computation load of matrix inversion at receiver side. The proposed low-complexity detectors are based on Neumann series expansion, successive over-relaxation (SOR), and symmetric successive over-relaxation (SSOR) principles. Simulation examples in the uplink scenario are given for the proposed low-complexity turbo detectors to demonstrate the comparisons and effectiveness of the proposed schemes.