Quarterly Financial Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 258,640	$ 271,160	$ 248,366	$ 259,090	$ 243,451	$ 256,675	$ 240,502	$ 246,025	$ 1,037,256	$ 986,653	$ 925,312
Consolidated net income	58,126	68,176	49,085	120,535	53,380	59,660	49,169	64,177
Net income available to Common Stockholders—Basic (shares)	$ 54,952	$ 64,461	$ 46,401	$ 113,309	$ 50,166	$ 56,070	$ 46,137	$ 60,222	$ 279,123	$ 212,596	$ 189,904
Weighted average Common Shares outstanding – Basic (shares)	181,664	181,649	180,312	179,560	179,140	178,400	177,098	177,048	180,805	177,928	173,994
Weighted average Common Shares outstanding—Diluted (shares)	192,458	192,400	191,860	191,248	191,154	190,526	189,246	189,154	191,995	190,110	186,850
Net income per Common Share outstanding—Basic (usd per share)	$ 0.30	$ 0.35	$ 0.26	$ 0.63	$ 0.28	$ 0.31	$ 0.26	$ 0.34	$ 1.54	$ 1.19	$ 1.09
Net income per Common Share outstanding—Diluted (usd per share)	$ 0.30	$ 0.35	$ 0.26	$ 0.63	$ 0.28	$ 0.31	$ 0.26	$ 0.34	$ 1.54	$ 1.19	$ 1.08