Leases - Summary of Minimum Future Rent Payments Receivable under Noncancelable Operating Leases (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 2,089
Operating Leases, Future Minimum Payments Receivable, Current	239,516
Operating Leases, Future Minimum Payments Receivable, in Two Years	204,139
Operating Leases, Future Minimum Payments Receivable, in Three Years	169,321
Operating Leases, Future Minimum Payments Receivable, in Four Years	141,865
Operating Leases, Future Minimum Payments Receivable, in Five Years	114,389
Operating Leases, Future Minimum Payments Receivable, Thereafter	399,892
Operating Leases, Future Minimum Payments Receivable	1,269,122
Capital Leases, Future Minimum Payments Due, Next Twelve Months	167
Operating Leases, Future Minimum Payments, Due in Two Years	1,861
Capital Leases, Future Minimum Payments Due in Two Years	167
Operating Leases, Future Minimum Payments, Due in Three Years	1,680
Capital Leases, Future Minimum Payments Due in Three Years	167
Operating Leases, Future Minimum Payments, Due in Four Years	1,547
Capital Leases, Future Minimum Payments Due in Four Years	150
Operating Leases, Future Minimum Payments, Due in Five Years	1,168
Capital Leases, Future Minimum Payments Due in Five Years	79
Operating Leases, Future Minimum Payments, Due Thereafter	0
Capital Leases, Future Minimum Payments Due Thereafter	1,497
Operating Leases, Future Minimum Payments Due	8,345
Capital Leases, Future Minimum Payments Due	$ 2,227