Schedule I Condensed Financial Information of Registrant Parent Company Only - Balance Sheets (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 06, 2017
Assets
Cash and cash equivalents	$ 1,101,893	$ 577,883
Short-term investments	59,474	520,877
Other assets	188,638	115,550
Total assets	13,265,619	11,333,368
Liabilities
Other liabilities	123,918	62,406
Dividends payable	137,056	116,287
Total liabilities	5,216,630	4,432,346
Common stock, $0.01 par value, 700,000,000 shares authorized and 461,004,742 and 404,729,616 shares issued and outstanding at December 31, 2019 and December 31, 2018, respectively	4,610	4,047
Preferred stock, $0.01 par value, 50,000,000 shares authorized and no shares outstanding at December 31, 2019 and 2018	0	0
Additional paid-in capital	7,817,582	6,648,430
Accumulated other comprehensive loss	(65,078)	(22,124)
Retained earnings	208,069	187,096
Total stockholders’ equity	8,048,989	6,901,022	$ 4,776,364	$ 3,516,673
Total liabilities and stockholders’ equity	$ 13,265,619	$ 11,333,368
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	700,000,000	700,000,000
Common stock, shares issued (in shares)	461,004,742	404,729,616
Common stock, shares outstanding (in shares)	461,004,742	404,729,616	300,278,938
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares outstanding (in shares)	0	0
Parent Company
Assets
Cash and cash equivalents	$ 13,912		$ 377,704
Restricted cash	0		48
Short-term investments	0		520,877
Other assets	159		2,150
Due from affiliates	838		133
Investment in subsidiaries	8,087,905		6,033,310
Total assets	8,102,814		6,934,222
Liabilities
Other liabilities	576		486
Dividends payable	137,056		116,287
Total liabilities	137,632		116,773
Common stock, $0.01 par value, 700,000,000 shares authorized and 461,004,742 and 404,729,616 shares issued and outstanding at December 31, 2019 and December 31, 2018, respectively	4,610		4,047
Preferred stock, $0.01 par value, 50,000,000 shares authorized and no shares outstanding at December 31, 2019 and 2018	0		0
Additional paid-in capital	7,817,582		6,648,430
Accumulated other comprehensive loss	(65,078)		(22,124)
Retained earnings	208,068		187,096
Total stockholders’ equity	7,965,182		6,817,449
Total liabilities and stockholders’ equity	$ 8,102,814		$ 6,934,222
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Common stock, shares authorized (in shares)	700,000,000		700,000,000
Common stock, shares issued (in shares)	404,729,616		300,278,938
Common stock, shares outstanding (in shares)	404,729,616		300,278,938
Preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000		50,000,000
Preferred stock, shares outstanding (in shares)	0		0