Changes in Total Real Estate (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate and Accumulated Depreciation [Line Items]
Balance, beginning of year	$ 4,044,650	$ 3,960,692	$ 2,584,987
Real Estate, Other Acquisitions	133,344	18,738	1,312,658
Improvements	64,714	67,850	61,256
Dispositions and other	14,602	2,630	(1,791)
Balance, end of year	$ 4,228,106	$ 4,044,650	$ 3,960,692