Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($)	3 Months Ended																12 Months Ended
	Dec. 31, 2019	[1]	Sep. 30, 2019	[1]	Jun. 30, 2019	[1]	Mar. 31, 2019	[1]	Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Numerator:
Net income	$ 72,000,000		$ 50,000,000		$ 39,000,000		$ 55,000,000		$ 120,000,000		$ 41,000,000		$ 107,000,000		$ 30,000,000		$ 215,695,961	[1],[2]	$ 298,124,983	[1],[2]	$ 326,777,744	[2]
Denominator:
Weighted average shares outstanding, Basic																	88,758,859		97,209,889		98,934,352
Basic EPS	$ 0.83		$ 0.59		$ 0.43		$ 0.59		$ 1.25		$ 0.42		$ 1.10		$ 0.31		$ 2.43	[1]	$ 3.07	[1]	$ 3.30
Denominator:
Weighted average shares outstanding, diluted																	89,291,176		97,898,242		99,621,199
Diluted EPS	$ 0.83		$ 0.59		$ 0.43		$ 0.58		$ 1.24		$ 0.42		$ 1.10		$ 0.30		$ 2.42	[1]	$ 3.05	[1]	$ 3.28

[1] The sum of the earnings per share for the four quarters may differ from annual earnings per share due to the required method of computing the weighted average shares in interim periods.

[2] Net income for years ended December 31, 2019, 2018, and 2017 was $215,695,961; $298,124,983 and $326,777,744, respectively.