Changes in Equity (Rollforward) (Details) $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($)
Balances	$ 3,195,068
Dividends declared	(44,269)
Share repurchases	(69,269)
Equity-based compensation	5,132
Comprehensive and net income (loss)	225,475
Balances	3,312,137
Common Stock
Balances	644
Balances	644
Treasury Stock
Balances	(665,297)
Share repurchases	(69,269)
Equity-based compensation	3,866
Balances	(730,700)
Additional Paid-In Capital
Balances	1,141,534
Equity-based compensation	1,337
Balances	1,142,871
Retained Earnings
Balances	2,874,693
Dividends declared	(44,269)
Equity-based compensation	(71)
Comprehensive and net income (loss)	227,551
Balances	3,057,904
Noncontrolling Interests
Balances	(156,506)
Comprehensive and net income (loss)	(2,076)
Balances	(158,582)
Redeemable Noncontrolling Interest
Balances	111,240
Balances	$ 111,240

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

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