Equity - Additional Information (Details) - shares	3 Months Ended	6 Months Ended
Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019
Partnership Exchangeable Units
Stockholders Equity [Line Items]
BKW reorganization into Partnership, Shares	45,325	141,190	42,923	29,432	186,515

The number of shares issued during the period upon the conversion of units. An example of a convertible unit is an umbrella partnership real estate investment trust unit (UPREIT unit).

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration