Nonbinary low-density-parity-check (NB-LDPC) codes, an extension of binary LDPC codes, provide stronger error-correcting capability than binary LDPC codes. However, the performance gain comes together with extraordinary increase on decoding complexity and memory requirement. Many simplification algorithms have been proposed in the literature, and the extended min-sum (EMS) algorithm is the one with minimal performance loss. In this brief, we present an efficient decoder architecture for quasi-cyclic NB-LDPC codes with the EMS algorithm. The throughput is improved by not only the double-throughput elementary check node unit but also overlapped processing for both check node and variable node units (VNUs). To reduce memory usage and computing complexity, edge-message hiding and simplified VNU are proposed as well. With these schemes, the postlayout results of a decoder for a (112, 56) NB-LDPC over GF(64) are presented. The core area occupies 2.24 mm2 and consumes 274 mW with a throughput of 124.6 Mb/s. Compared to prior NB-LDPC decoders with a similar code rate, the proposed decoder achieves better hardware efficiency and energy efficiency.