Fair Value Measurements - Estimated Fair Value of Senior Notes (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 1,037,225,000	$ 989,422,000
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,189,018,000	1,051,025,000
Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 1,037,225,000	989,422,000
$250 million 5.625% Senior Notes due February 2020, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate, stated percentage	5.625%
Debt instrument, face amount	$ 250,000,000
Carrying Amount	0	249,909,000
$250 million 5.625% Senior Notes due February 2020, net | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	250,400,000
$250 million 5.625% Senior Notes due February 2020, net | Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 0	249,909,000
$250 million 5.500% Senior Notes due January 2024, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate, stated percentage	5.50%
Debt instrument, face amount	$ 250,000,000
Carrying Amount	249,174,000	249,005,000
$250 million 5.500% Senior Notes due January 2024, net | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	270,388,000	272,083,000
$250 million 5.500% Senior Notes due January 2024, net | Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 249,174,000	249,005,000
$300 million 3.850% Senior Notes due January 2030, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate, stated percentage	3.85%
Debt instrument, face amount	$ 300,000,000
$300 million 3.850% Senior Notes due January 2030, net | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	313,505,000	0
$300 million 3.850% Senior Notes due January 2030, net | Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 297,400,000	0
$500 million 6.000% Senior Notes due January 2043, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate, stated percentage	6.00%
Debt instrument, face amount	$ 500,000,000
Carrying Amount	490,651,000	490,508,000
$500 million 6.000% Senior Notes due January 2043, net | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	605,125,000	528,542,000
$500 million 6.000% Senior Notes due January 2043, net | Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 490,651,000	$ 490,508,000