Stockholders' Equity - Summary of Changes in Noncontrolling Interest (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Beginning of Period			$ 41,877
Net Income	$ 556	$ 165	649	$ 269
Other Comprehensive Income (Loss) (Including a Reallocation of $2 and $7)			6,479
StockIssuedDuringPeriodValueConversionOfUnits			0	0
Reallocation - Additional Paid-in-Capital			0
Noncontrolling Interest, End of Period	41,574		41,574
Noncontrolling Interest
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Beginning of Period			41,877	44,369
Net Income			649	269
Unit Distributions			(1,113)	(915)
Other Comprehensive Income (Loss) (Including a Reallocation of $2 and $7)			248	(127)
StockIssuedDuringPeriodValueConversionOfUnits			(100)	(1,333)
Reallocation - Additional Paid-in-Capital			13	(91)
Noncontrolling Interest, End of Period	$ 41,574	$ 42,172	$ 41,574	$ 42,172