Unaudited Quarterly Results (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information

Summarized quarterly financial data (unaudited) for the years ended December 31, 2017 and 2016 are set forth in the following tables.

	First Quarter Ended March 31, 2017		Second Quarter Ended June 30, 2017*		Third Quarter Ended September 30, 2017		Fourth Quarter Ended December 31, 2017**
Revenues	$	1,318,991	$	1,470,116	$	1,500,673	$	1,582,447
Net income	$	248,931	$	387,744	$	388,317	$	173,519
Net income per share - basic	$	2.36	$	3.66	$	3.64	$	1.62
Net income per share - diluted	$	2.16	$	3.34	$	3.32	$	1.50
	First Quarter Ended March 31, 2016***		Second Quarter Ended June 30, 2016		Third Quarter Ended September 30, 2016		Fourth Quarter Ended December 31, 2016
Revenues	$	1,200,849	$	1,212,629	$	1,220,122	$	1,226,827
Net income	$	181,385	$	196,218	$	264,804	$	253,115
Net income per share - basic	$	1.74	$	1.88	$	2.53	$	2.41
Net income per share - diluted	$	1.59	$	1.69	$	2.27	$	2.19