Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Retirement Plans [Abstract]
Matching Contributions Equal To Employees Contributions	25.00%	25.00%	25.00%
Maximum contributed compensation	4.00%	4.00%	4.00%
Additional matching contribution	12.50%	12.50%	12.50%
Expense related to retirement savings plan	$ 8.2	$ 6.6	$ 7.1

Percentage of additional matching contribution by the employer into the retirement plan.

No definition available.

Name:	bkd_AdditionalMatchingContribution
Namespace Prefix:	bkd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of the employer's matching contribution to the plan.

+ References

No definition available.

+ Details

Name:	bkd_MatchingContributionsEqualToEmployeesContributions
Namespace Prefix:	bkd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration