Nature of Business and Financial Statement Presentation - Non-cash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Other Significant Noncash Transactions [Line Items]
Dividends declared, but not paid	$ 5,133	$ 44,600	$ 44,036
Accounts payable related to construction in progress	4,900	14,300
Building [Member]
Other Significant Noncash Transactions [Line Items]
Assumption of buildings due to ground lease terminations	$ 3,000	$ 0