Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 6 months ended Jun. 30, 2018 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss		Total stockholders' equity	Noncontrolling Interests
Balance value at Dec. 31, 2017	$ 3,483,025	$ 1	$ 2,236,351	$ 1,311,112	$ (67,509)		$ 3,479,955	$ 3,070
Balance shares at Dec. 31, 2017	110,925	110,925
Cumulative-effect adjustment (Note 1) | Accounting Standards Update 2016-01				40,550	(40,550)	[1]
Net income (loss) for six months ended June 30, 2018	$ 231,263			231,367			231,367	(104)
Dividends on common shares	(84,717)			(84,717)			(84,717)
Shares issued in connection with share-based compensation plans, value	(11,229)		(9,555)	(1,674)			(11,229)
Shares issued in connection with share-based compensation plans, shares		733
Share-based compensation	27,135		27,135				27,135
Net activity related to noncontrolling interests	(926)		322				322	(1,248)
Other comprehensive loss (Note 13)	(73,329)				(73,310)		(73,310)	(19)
Balance value at Jun. 30, 2018	$ 3,571,222	$ 1	$ 2,254,253	$ 1,496,638	$ (181,369)		$ 3,569,523	$ 1,699
Balance shares at Jun. 30, 2018	111,658	111,658

[1] Upon adoption of new accounting guidance on January 1, 2018, the Company recognized a cumulative-effect adjustment to retained earnings for cumulative net unrealized gains related to its investments in equity securities. See Note 1 Basis of Condensed Consolidated Financial Statements for further discussion of the new guidance.