CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) - USD ($) $ in Thousands		Total	Common Stock	Treasury Stock	Retained Earnings		Accumulated Other Comprehensive Income (Loss)		Noncontrolling Interests	APS	APS Common Stock	APS Additional Paid-In Capital	APS Retained Earnings		APS Accumulated Other Comprehensive Income (Loss)		APS Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2017			111,816,170	64,463							71,264,947
Balance at beginning of period at Dec. 31, 2017		$ 5,135,730	$ 2,614,805	$ (5,624)	$ 2,442,511		$ (45,002)		$ 129,040	$ 5,385,869	$ 178,162	$ 2,571,696	$ 2,533,954		$ (26,983)		$ 129,040
Increase (Decrease) in Shareholders' Equity
Net income		8,094			3,221				4,873	14,472			9,599				4,873
Other comprehensive income		1,213					1,213			1,170					1,170
Other										1							1
Dividends on common stock		(16)			(16)
Issuance of common stock (in shares)			145,793
Issuance of common stock		5,456	$ 5,456
Purchase of treasury stock (in shares)	[1]			(81,177)
Purchase of treasury stock	[1]	(6,277)		$ (6,277)
Reissuance of treasury stock for stock-based compensation and other (in shares)				116,543
Reissuance of treasury stock for stock-based compensation and other		9,471		$ 9,470	0				1
Reclassification of income tax effects related to new tax reform		(8,552)			8,552	[2]	(8,552)	[2]		(5,038)			5,038	[2]	(5,038)	[2]
Ending balance (in shares) at Mar. 31, 2018			111,961,963	29,097							71,264,947
Balance at end of period at Mar. 31, 2018		$ 5,153,671	$ 2,620,261	$ (2,431)	2,454,268		(52,341)		133,914	5,401,512	$ 178,162	2,571,696	2,548,591		(30,851)		133,914
Beginning balance (in shares) at Dec. 31, 2018		112,159,896	112,159,896	58,135							71,264,947
Balance at beginning of period at Dec. 31, 2018		$ 5,348,705	$ 2,634,265	$ (4,825)	2,641,183		(47,708)		125,790	5,786,797	$ 178,162	2,721,696	2,788,256		(27,107)		125,790
Increase (Decrease) in Shareholders' Equity
Net income		22,791			17,918				4,873	33,149			28,276				4,873
Other comprehensive income		1,207					1,207			1,080					1,080
Dividends on common stock		(15)			(15)
Issuance of common stock (in shares)			180,426
Issuance of common stock		9,798	$ 9,798
Purchase of treasury stock (in shares)	[1]			(75,791)
Purchase of treasury stock	[1]	(6,882)		$ (6,882)
Reissuance of treasury stock for stock-based compensation and other (in shares)				70,655
Reissuance of treasury stock for stock-based compensation and other		$ 6,121		$ 6,121	0				0
Ending balance (in shares) at Mar. 31, 2019		112,340,322	112,340,322	63,271							71,264,947
Balance at end of period at Mar. 31, 2019		$ 5,381,725	$ 2,644,063	$ (5,586)	$ 2,659,086		$ (46,501)		$ 130,663	$ 5,821,026	$ 178,162	$ 2,721,696	$ 2,816,532		$ (26,027)		$ 130,663

[1] Primarily represents shares of common stock withheld from certain stock awards for tax purposes.

[2] In 2018, the Company adopted new accounting guidance and elected to reclassify income tax effects of the Tax Cuts and Jobs Act of 2017 (the “Tax Act”) on items within accumulated other comprehensive income to retained earnings.