CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net (loss) income attributable to common stockholders	$ (3,175)	$ 14,147	$ 12,431	$ (10,982)
Unrealized gain (loss) on derivative instruments	2,311	(1,450)	(3,642)	1,075
Comprehensive (loss) income attributable to common stockholders	$ (864)	$ 12,697	$ 8,789	$ (9,907)