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Stock-based Compensation - Summary of the Status of the Trust's Non-Vested Restricted Common Shares (Details) - 2013 Plan - Restricted common shares
3 Months Ended
Mar. 31, 2018
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]  
Non-vested at the beginning of the period (in shares) | shares 173,276
Granted (in shares) | shares 178,700
Vested (in shares) | shares (133,052)
Non-vested at the end of the period (in shares) | shares 218,924
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]  
Non-vested at beginning of period (in dollars per share) | $ / shares $ 19.36
Granted (in dollars per share) | $ / shares 14.78
Vested (in dollars per share) | $ / shares 19.63
Non-vested at end of period (in dollars per share) | $ / shares $ 15.45