Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Capitalized costs	$ 11,100,000	$ 10,900,000	$ 10,500,000
Impairment charges related to consolidated real estate investment	38,100,000	72,600,000	126,500,000
Interest paid	243,200,000	218,400,000	209,300,000
Capitalized interest paid	8,700,000	8,800,000	13,300,000
Impairment of joint venture investments	30,652,000	980,000	26,671,000
Accounts receivable, unrecoverable amount	7,200,000	10,000,000
Allowance for straight line rent	3,600,000	3,900,000
Straight line rent receivable, net	63,800,000	61,900,000
Stock-based compensation cost recognized by the company	9,100,000	7,400,000	6,400,000
Accelerated vesting of awards due to employee severance charges	$ 1,400,000	$ 100,000	$ 200,000