Supplementary Quarterly Financial Data (Unaudited) - (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of Supplementary Quarterly Financial Data

SUPPLEMENTARY QUARTERLY FINANCIAL DATA (UNAUDITED)

	For the Three Months Ended
	March 31, 2017		June 30, 2017		September 30, 2017		December 31, 2017
Revenues	$	263,008	$	276,003	$	284,156	$	281,842
Cost of operations	138,805		139,596		144,275		140,728
Revenues less cost of operations	$	124,203	$	136,407	$	139,881	$	141,114
Net income	$	89,734	$	94,098	$	101,075	$	229,315
Net income attributable to common stockholders	$	82,282	$	87,006	$	93,764	$	215,983
Earnings per common share—basic	$	0.65	$	0.69	$	0.74	$	1.71
Earnings per common share—diluted	$	0.64	$	0.69	$	0.74	$	1.69
	For the Three Months Ended
	March 31, 2016		June 30, 2016		September 30, 2016		December 31, 2016
Revenues	$	229,403	$	244,273	$	257,183	$	261,016
Cost of operations	135,775		133,971		134,459		137,832
Revenues less cost of operations	$	93,628	$	110,302	$	122,724	$	123,184
Net income	$	89,407	$	90,040	$	127,226	$	90,416
Net income attributable to common stockholders	$	82,592	$	83,044	$	118,088	$	82,403
Earnings per common share—basic	$	0.66	$	0.66	$	0.94	$	0.65
Earnings per common share—diluted	$	0.66	$	0.66	$	0.93	$	0.65