Notional Amounts of Swap Agreement, Weighted Average Interest Rates and Remaining Term (Detail) - Interest rate swap agreements - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Notional Amount	$ 1,276,000	$ 2,501,000
Weighted Average Fixed Rate	2.10%	2.02%
Remaining Term in Months	55 months	48 months
Less than 1 year
Derivative [Line Items]
Notional Amount	$ 316,000	$ 541,000
Weighted Average Fixed Rate	1.69%	1.70%
Remaining Term in Months	4 months	7 months
1 year to 2 years
Derivative [Line Items]
Notional Amount	$ 25,000	$ 190,000
Weighted Average Fixed Rate	1.50%	1.63%
Remaining Term in Months	20 months	21 months
2 years to 3 years
Derivative [Line Items]
Notional Amount	$ 55,000	$ 335,000
Weighted Average Fixed Rate	1.48%	1.65%
Remaining Term in Months	31 months	34 months
3 years to 4 years
Derivative [Line Items]
Notional Amount	$ 115,000	$ 295,000
Weighted Average Fixed Rate	1.52%	1.71%
Remaining Term in Months	43 months	45 months
4 years to 5 years
Derivative [Line Items]
Notional Amount	$ 225,000	$ 550,000
Weighted Average Fixed Rate	1.73%	2.18%
Remaining Term in Months	60 months	61 months
5 years to 7 years
Derivative [Line Items]
Notional Amount	$ 390,000	$ 390,000
Weighted Average Fixed Rate	2.60%	2.51%
Remaining Term in Months	85 months	85 months
7 years to 10 years
Derivative [Line Items]
Notional Amount	$ 150,000	$ 200,000
Weighted Average Fixed Rate	2.97%	2.94%
Remaining Term in Months	102 months	104 months