Consolidated Unaudited Pro Forma Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Business Acquisition, Pro Forma Information [Line Items]
Total revenue, as reported	$ 67,607	$ 62,395	$ 58,622	$ 58,251	$ 54,922	$ 52,193	$ 47,873	$ 45,796	$ 246,875	$ 200,784	$ 195,798
Pro forma revenue									255,992	213,551
Net income (loss) allocable to common shares, as reported	(134,493)	(17,106)	(65,877)	(90,532)	(50,449)	(18,386)	(6,951)	(107,019)	(308,008)	(182,805)	(51,130)
Pro forma net income (loss) allocable to common shares									$ (304,588)	$ (178,470)