Organization and Significant Accounting Policies - Supplemental Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Accounting Policies [Abstract]
Interest paid, including interest capitalized	$ 30,977	$ 33,476
Income tax payments, net	1,039	1,082
Non-cash investing and financing activities:
Dividends and distributions payable	21,833	17,932
Conversions of redeemable common units	784
Common stock 401k matching contribution	658	670
Construction and property capital expenditure cost accruals, increase (decrease)	(3,421)	(3,754)
Adjustments to equity related to redeemable common units, net increase (decrease)	$ (531)	$ 767