Blazars are known to show periods of quiescence followed by outbursts visible throughout the electromagnetic spectrum. We present a novel maximum likelihood approach to capture this bimodal behavior by examining blazar radio variability in the flux-density domain. We separate quiescent and flaring components of a sources light curve by modeling its flux-density distribution as a series of off and on states. Our modeling allows us to extract information regarding the flaring ratio, duty cycle, and the modulation index in the off-state, in the on-state, as well as throughout the monitoring period of each blazar. We apply our method to a flux-density-limited subsample from the Owens Valley Radio observatorys 15 GHz blazar monitoring program, and explore differences in the variability characteristics between BL Lacs and FSRQs as well as between $gamma$-ray detected and non-detected sources. We find that: (1) BL Lacs are more variable and have relatively larger outbursts than the FSRQs, (2) unclassified blazar candidates in our sample show similar variability characteristics as the FSRQs, and (3) $gamma$-ray detected differ from the $gamma$-ray non-detected sources in all their variability properties, suggesting a link between the production of $gamma$-rays and the mechanism responsible for the radio variability. Finally, we fit distributions for blazar flaring ratios, duty cycles, and on- and off- modulation indices that can be used in population studies of variability-dependent blazar properties.
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