Summary of Quarterly Results - Summary of Unaudited Quarterly Financial Information(Detail) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Results Of Operations [Line Items]
Impairment losses	$ 54,000	$ 51,400	$ 28,700	$ 6,200	$ 2,300	$ 16,100	$ 1,300
Gains on sales of discontinued operations								$ 0	$ 0	$ 78,512
Gain Loss On Sale Of Real Estate	$ 13,100	$ 12,400						$ 259	$ 1,774