Organization and Summary of Significant Accounting Policies - Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2019		Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basic EPS impact from tax benefit from US tax reform												$ 1.92
Diluted EPS impact from tax benefit from US tax reform												$ 1.91
Sale of Canadian subsidiary and assets										$ (16,860,000)	$ 0	$ 0
Diluted EPS impact from sale of Canadian assets	$ 0.05
Income (numerator):
Net income - basic and diluted	$ 193,946,000	[1]	$ 158,162,000	$ 236,557,000	$ 186,976,000	$ 197,738,000	$ 314,169,000	$ 242,464,000	$ 233,946,000	$ 775,641,000	$ 988,317,000	$ 789,447,000
Weighted average shares - basic										370,699	371,854	371,066
Non-vested restricted stock										1,839	2,984	2,702
Weighted average shares - diluted										372,538	374,838	373,768
Net income per share:
Basic (in dollars per share)	$ 0.53	[1]	$ 0.43	$ 0.63	$ 0.50	$ 0.53	$ 0.84	$ 0.65	$ 0.63	$ 2.09	$ 2.66	$ 2.13
Diluted (in dollars per share)	$ 0.53	[1]	$ 0.43	$ 0.63	$ 0.50	$ 0.53	$ 0.84	$ 0.65	$ 0.63	$ 2.08	$ 2.64	$ 2.11

[1] In the fourth quarter of 2019, the Company sold its Canadian subsidiary and associated properties and a $16.9 million ($0.05 per basic and diluted share) decrease in income tax expense and corresponding increase in net income was recognized as discussed in Note 9. Income Taxes