CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
CONSOLIDATED STATEMENTS OF OPERATIONS
REVENUES									$ 3,980,067	$ 2,940,163	$ 2,988,310
OPERATING EXPENSES									3,699,081	2,841,885	2,924,540
OPERATING INCOME									280,986	98,278	63,770
OTHER INCOME (COSTS)
Interest and dividend income									1,275	3,616	6,453
Interest and other related financing costs									(8,904)	(11,697)	(11,467)
Other, net									3,797	2,299	(7,285)
Total other costs									(3,832)	(5,782)	(12,299)
INCOME BEFORE INCOME TAXES									277,154	92,496	51,471
INCOME TAX PROVISION									63,633	21,396	11,486
NET INCOME									$ 213,521	$ 71,100	$ 39,985
EARNINGS PER COMMON SHARE
Basic									$ 8.38	$ 2.80	$ 1.56
Diluted									$ 7.98	$ 2.69	$ 1.51
AVERAGE COMMON SHARES OUTSTANDING
Basic									25,471,939	25,410,232	25,535,529
Diluted									26,772,126	26,422,523	26,450,055
CASH DIVIDENDS DECLARED PER COMMON SHARE	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.32	$ 0.32	$ 0.32