Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Related Party Transaction [Line Items]
Expense incurred as result of multiple service agreements	$ 2,707	$ 2,414
Intercompany short-term note receivable	0	$ 25,000
Interest on intercompany note receivable		0.36%
Interest income accrued and/or received due to intercompany arrangements	0	$ 17
AEGON USA Realty Advisors, LLC
Related Party Transaction [Line Items]
Expense incurred as result of multiple service agreements	51	42
AEGON USA Investment Management LLC
Related Party Transaction [Line Items]
Expense incurred as result of multiple service agreements	491	493
Transamerica Capital, Inc.
Related Party Transaction [Line Items]
Expense incurred as result of multiple service agreements	5,558	6,152
Transamerica Asset Management, Inc.
Related Party Transaction [Line Items]
Expense incurred as result of multiple service agreements	79	76
Distribution and shareholder services agreement
Related Party Transaction [Line Items]
Revenue from participation agreement	$ 600	$ 491