Real Estate and Accumulated Depreciation - Changes in Accumulated Depreciation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
SEC Schedule III, Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, Beginning of Year	$ 642,439	$ 609,986	$ 581,851
Depreciation for Year	83,835	88,123	85,849
Disposition of Assets	(43,603)	(30,591)	(28,606)
Write-off of Fully Depreciated Assets	(29,700)	(25,079)	(29,108)
Balance, End of Year	$ 652,971	$ 642,439	$ 609,986