Expiration Years of Minimum Alternate Tax Credit (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Tax Credit Carryforward [Line Items]
Less: Valuation allowance	$ (9,167)	$ (5,454)
Total (net of valuation allowance)	31,999	$ 37,786
Minimum Alternate Tax (MAT)
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	35,970
Less: Valuation allowance	(5,190)
Total (net of valuation allowance)	30,780
Minimum Alternate Tax (MAT) | 2017-18
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	190
Minimum Alternate Tax (MAT) | 2018-19
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	260
Minimum Alternate Tax (MAT) | 2019-20
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	950
Minimum Alternate Tax (MAT) | 2020-21
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	1,590
Minimum Alternate Tax (MAT) | 2021-22
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	780
Minimum Alternate Tax (MAT) | 2022-23
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	5,860
Minimum Alternate Tax (MAT) | 2023-24
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	6,940
Minimum Alternate Tax (MAT) | 2024-25
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	7,620
Minimum Alternate Tax (MAT) | 2025-26
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	9,800
Minimum Alternate Tax (MAT) | 2026-27
Tax Credit Carryforward [Line Items]
Minimum Alternate Tax Credit	$ 1,980