Aggregate Consolidated Scheduled Debt Repayment (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Debt Disclosure [Abstract]
2018	$ 23,347
2019	185,035
2020	1,688	[1]
2021	1,846
2022	11,950
Later	32,926
Total	$ 256,792

[1] Includes repayment of $181.1 million of outstanding borrowings under the terms of our $250 million revolving credit agreement.