Derivatives - Summary of Gross and Net Fair Values of Derivatives Outstanding Included in Other Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Offsetting Liabilities [Line Items]
Net amounts in the consolidated balance sheets	$ 16,839
Interest Rate Swap | Counterparty A
Offsetting Liabilities [Line Items]
Gross amounts of recognized liabilities	15,009	$ 11,833
Gross amounts offset in the consolidated balance sheets	(7,232)	(4,491)
Net amounts in the consolidated balance sheets	$ 7,777	$ 7,342