Noncontrolling Interests (Redeemable Preferred Units) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Balance			$ 55,652	$ 55,652
Net income	765	842	1,566	1,665
Distributions			(1,566)	(1,665)
Conversion of redeemable preferred units to common units			(4,115)
Balance	$ 51,537	$ 55,652	$ 51,537	$ 55,652