Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2015	$ (572,335)	$ 5,588	$ 32	$ 4,134	$ 5,608,881	$ 5,046,300	$ 135,651	$ 5,181,951
Balance (in shares) at Dec. 31, 2015			32	413,431
Comprehensive income:
Net income	140,713					140,713	1,441	142,154
Other comprehensive income, net of tax:
Change in unrealized gain on marketable securities		2				2		2
Change in unrealized loss on interest rate swaps		(604)				(604)		(604)
Change in foreign currency translation adjustment		2,510				2,510		2,510
Redeemable noncontrolling interests income							(1,078)	(1,078)
Dividends	(118,481)					(118,481)		(118,481)
Distributions to noncontrolling interests							(1,276)	(1,276)
Issuance of common stock (in shares)				4,487
Issuance of common stock				$ 45	100,911	100,956		100,956
Surrender of restricted stock (in shares)				(228)
Surrender of restricted stock				$ (2)	(5,906)	(5,908)		(5,908)
Exercise of common stock options (in shares)				592
Exercise of common stock options				$ 6	10,539	10,545		10,545
Amortization of equity awards					6,586	6,586		6,586
Balance at the end of the year at Mar. 31, 2016	(550,103)	7,496	$ 32	$ 4,183	5,721,011	5,182,619	134,738	5,317,357
Balance (in shares) at Mar. 31, 2016			32	418,282
Balance at Dec. 31, 2015	(572,335)	5,588	$ 32	$ 4,134	5,608,881	5,046,300	135,651	5,181,951
Balance (in shares) at Dec. 31, 2015			32	413,431
Other comprehensive income, net of tax:
Net income	140,713					140,713	1,441	142,154
Dividends	118,481					118,481		118,481
Balance at Dec. 31, 2016	(676,867)	5,766	$ 32	$ 4,250	5,922,958	5,256,139	146,735	5,402,874
Balance (in shares) at Dec. 31, 2016			32	425,034
Comprehensive income:
Net income	76,733					76,733	1,482	78,215
Other comprehensive income, net of tax:
Change in unrealized gain on marketable securities		28				28		28
Change in unrealized loss on interest rate swaps		188				188		188
Change in foreign currency translation adjustment		503				503		503
Redeemable noncontrolling interests income							(1,066)	(1,066)
Dividends	126,476					126,476		126,476
Distributions to noncontrolling interests							(1,250)	(1,250)
Issuance of common stock (in shares)				776
Issuance of common stock				$ 8	(8)
Surrender of restricted stock (in shares)				(200)
Surrender of restricted stock				$ (2)	(4,989)	(4,991)		(4,991)
Exercise of common stock options (in shares)				30
Exercise of common stock options					560	560		560
Amortization of equity awards					8,651	8,651		8,651
Balance at the end of the year at Mar. 31, 2017	(726,610)	6,485	$ 32	$ 4,256	5,927,172	5,211,335	148,211	5,359,546
Balance (in shares) at Mar. 31, 2017			32	425,640
Balance at Dec. 31, 2016	(676,867)	$ 5,766	$ 32	$ 4,250	$ 5,922,958	5,256,139	146,735	5,402,874
Balance (in shares) at Dec. 31, 2016			32	425,034
Other comprehensive income, net of tax:
Contributions from noncontrolling interests							2,310	2,310
Net income	76,733					76,733	$ 1,482	78,215
Dividends	$ (126,476)					$ (126,476)		$ (126,476)