Related Party Transactions - Summary of Fees and Expenses Incurred by Company (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Expensed:
Acquisition fees, incurred	$ 1,690	$ 5,627	$ 3,432	$ 10,961
Asset management fees, incurred	7,393	6,077	22,029	15,831
Other expense reimbursements, incurred	187	182	588	691
Total	9,270	11,886	26,049	27,483
Acquisition fees, payable	0		0		0
Asset management fees, payable	34		34		13
Other expense reimbursements, receivable (payable)	51		51		73
Total	85		85		86
Additional Paid-In Capital:
Sales commissions, incurred	0	14,468	0	49,245
Dealer manager fees, incurred	0	5,419	0	18,294
Offering expenses, incurred	209	3,774	850	13,101
Total	209	23,661	850	80,640
Sales commissions, payable	0		0		0
Dealer manager fees, payable	0		0		0
Offering expenses, payable	81		81		139
Total	$ 81		$ 81		$ 139