Consolidated Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended																																				3 Months Ended								12 Months Ended
	Dec. 31, 2020	Nov. 30, 2020	Oct. 31, 2020	Sep. 30, 2020	Aug. 31, 2020	Jul. 31, 2020	Jun. 30, 2020	May 31, 2020	Apr. 30, 2020	Mar. 31, 2020	Feb. 29, 2020	Jan. 31, 2020	Dec. 31, 2019	Nov. 30, 2019	Oct. 31, 2019	Sep. 30, 2019	Aug. 31, 2019	Jul. 31, 2019	Jun. 30, 2019	May 31, 2019	Apr. 30, 2019	Mar. 31, 2019	Feb. 28, 2019	Jan. 31, 2019	Dec. 31, 2018	Nov. 30, 2018	Oct. 31, 2018	Sep. 30, 2018	Aug. 31, 2018	Jul. 31, 2018	Jun. 30, 2018	May 31, 2018	Apr. 30, 2018	Mar. 31, 2018	Feb. 28, 2018	Jan. 31, 2018	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Total revenue																																					$ 418,076	$ 404,572	$ 414,636	$ 414,341	$ 397,529	$ 374,247	$ 365,450	$ 354,365	$ 1,651,625	$ 1,491,591	$ 1,327,838
Depreciation and amortization expense																																					175,041	169,084	168,328	164,585	156,594	149,424	150,426	137,517	677,038	593,961	539,780
Interest expense																																					78,764	76,806	77,841	75,925	75,073	73,410	72,488	70,020	309,336	290,991	266,020
Other expenses																																					72,099	151,611	62,222	53,811	52,269	52,139	54,143	42,861	339,743	201,412
Net income																																					118,150	23,143	108,070	147,143	129,553	101,275	95,420	111,230	396,506	437,478	364,598
Net income available to common stockholders																																					$ 117,931	$ 22,904	$ 107,824	$ 146,827	$ 129,297	$ 101,049	$ 95,194	$ 110,942	$ 395,486	$ 436,482	$ 363,614
Net income per common share, basic (in dollars per share)																																					$ 0.33	$ 0.07	$ 0.31	$ 0.44					$ 1.15	$ 1.38	$ 1.26
Net income per common share, diluted (in dollars per share)																																					0.33	0.07	0.31	0.44					1.14	1.38	1.26
Net income per common share, basic and diluted (in dollars per share)																																									$ 0.39	$ 0.32	$ 0.31	$ 0.37		1.38
Dividends paid per common share (in dollars per share)	$ 0.2340	$ 0.2340	$ 0.2340	$ 0.2335	$ 0.2335	$ 0.2335	$ 0.2330	$ 0.2330	$ 0.2330	$ 0.2325	$ 0.2325	$ 0.2275	$ 0.2270	$ 0.2270	$ 0.2270	$ 0.2265	$ 0.2265	$ 0.2265	$ 0.2260	$ 0.2260	$ 0.2260	$ 0.2255	$ 0.2255	$ 0.2210	$ 0.2205	$ 0.2205	$ 0.2205	$ 0.2200	$ 0.2200	$ 0.2200	$ 0.2195	$ 0.2195	$ 0.2195	$ 0.2190	$ 0.2190	$ 0.2125	$ 0.7020	$ 0.7005	$ 0.6990	$ 0.6925	$ 0.6810	$ 0.6795	$ 0.6780	$ 0.6720	$ 2.7940	$ 2.7105	$ 2.6305