Consolidated Statement Of Equity - 9 months ended Sep. 30, 2016 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Cumulative Dividends In Excess Of Net Income [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Parent [Member]	Noncontrolling Interest [Member]
Balance, shares at Dec. 31, 2015	38,396,727	38,396,727
Balance, value at Dec. 31, 2015	$ 1,142,460	$ 384	$ 1,085,136	$ 19,862	$ 27,910	$ 1,133,292	$ 9,168
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	110,352			110,352	(19,454)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	90,898					90,898
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	1,176						1,176
Comprehensive income	92,074
Distributions to noncontrolling interest	$ (26,413)		(16,069)			(16,069)	(10,344)
Stock Issued During Period, Shares, New Issues	1,395,642
Stock Issued During Period, Value, New Issues	$ 104,190	$ 14	104,176			104,190
Adjustments Related to Tax Withholding for Share-based Compensation	(1,133)		1,133			1,133
Shares issued on stock options exercised, shares		55,491
Stock Issued During Period, Value, Stock Options Exercised	(3)		(3)			(3)
Share-based compensation	1,481		1,481			1,481
Dividends declared, $1.54 per share	$ (105,666)			(105,666)		(105,666)
Balance, shares at Sep. 30, 2016	39,847,860	39,847,860
Balance, value at Sep. 30, 2016	$ 1,206,990	$ 398	$ 1,173,588	$ 24,548	$ 8,456	$ 1,206,990	$ 0