Fair Value Measurement - Amount of Gains and Losses from Changes in Fair Value Included in Earnings (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Change in fair value	$ 1,079	$ (2,482)
Construction [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Change in fair value	1,079	(2,482)
Total change in fair value	$ 1,079	$ (2,482)