Earnings Per Share (Details) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1.5	1.6	1.6	1.7

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bkd_AntidilutiveSecuritiesExcludedFromDilutedNetLossAmount

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bkd

Data Type:

xbrli:sharesItemType

Balance Type:

na

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duration