Consolidated Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended																																				3 Months Ended								12 Months Ended
	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, 2017	Nov. 30, 2017	Oct. 31, 2017	Sep. 30, 2017	Aug. 31, 2017	Jul. 31, 2017	Jun. 30, 2017	May 31, 2017	Apr. 30, 2017	Mar. 31, 2017	Feb. 28, 2017	Jan. 31, 2017	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 revenue																																					$ 397,529	$ 374,247	$ 365,450	$ 354,365	$ 342,576	$ 338,081	$ 328,886	$ 318,295	$ 1,491,591	$ 1,327,838	$ 1,215,768
Depreciation and amortization expense																																					156,594	149,424	150,426	137,517	137,711	136,967	133,999	131,103	593,961	539,780	498,788
Interest expense																																					75,073	73,410	72,488	70,020	70,635	69,342	66,628	59,415	290,991	266,020	247,413
Other expenses																																					52,269	52,139	54,143	42,861	54,752	40,302	39,349	47,680	201,412	182,083
Net income																																					129,553	101,275	95,420	111,230	85,303	99,283	96,697	83,315	437,478	364,598	319,318
Net income available to common stockholders																																					$ 129,297	$ 101,049	$ 95,194	$ 110,942	$ 85,072	$ 98,999	$ 96,380	$ 83,163	$ 436,482	$ 363,614	$ 301,514
Net income per common share, basic and diluted (in dollars per share)																																					$ 0.39	$ 0.32	$ 0.31	$ 0.37	$ 0.29	$ 0.34	$ 0.34	$ 0.29	$ 1.38	$ 1.26	$ 1.10
Dividends paid per common share (in dollars per share)	$ 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	$ 0.2120	$ 0.2120	$ 0.2120	$ 0.2115	$ 0.2115	$ 0.2115	$ 0.2110	$ 0.2110	$ 0.2110	$ 0.2105	$ 0.2105	$ 0.2025	$ 0.6810	$ 0.6795	$ 0.6780	$ 0.6720	$ 0.6615	$ 0.6600	$ 0.6585	$ 0.6505	$ 2.7105	$ 2.6305	$ 2.5270