Commitments and Contingencies Purchase Commitments (Details) (Purchase Commitment [Member], Private Capital Management Segment [Member], USD $) (Detail) (Purchase Commitment [Member], Private Capital Management Segment [Member], USD $)	9 Months Ended
	Sep. 30, 2014 Property Agreement
Purchase Commitment [Member] | Private Capital Management Segment [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of purchase and sale agreements	70
Percentage of voting interests acquired	100.00%
Number of properties acquired	303
Aggregate purchase price	$ 1,200,000,000
Property escrow deposit	$ 36,900,000