Stockholders' Equity - Changes in Noncontrolling Interest (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Class of Stock [Line Items]
Noncontrolling Interest, Beginning of Period			$ 42,274
Net Income (Loss)	219	277	244	(768)
Common Stock and Unit Distributions			(29,074)
Conversion of Units to Common Stock			0	0
Noncontrolling Interest, End of Period	43,869		43,869
Noncontrolling Interest
Class of Stock [Line Items]
Noncontrolling Interest, Beginning of Period			42,274	45,919
Net Income (Loss)			244	(768)
Common Stock and Unit Distributions			(1,183)	0
Other Comprehensive Income			121	233
Conversion of Units to Common Stock			(943)	(2,710)
Reallocation—Additional Paid in Capital			3,325	1,834
Reallocation-Other Comprehensive Income			31	89
Noncontrolling Interest, End of Period	$ 43,869	$ 44,597	$ 43,869	$ 44,597