Shareholders' Equity - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Dividends paid by subsidiaries to parent company	$ 480,000	$ 448,000	$ 454,000
Maximum amount of dividends expected to be available from subsidiaries without regulatory approval during next year	412,000
Restricted net assets	1,000,000
Retained earnings restricted by lenders' covenants	4,000,000
Retained earnings	$ 5,551,329	$ 5,213,468