Consolidated Statement Of Equity - 9 months ended Sep. 30, 2015 - 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, 2014	37,485,902	37,485,902
Balance, value at Dec. 31, 2014	$ 1,049,933	$ 375	$ 1,033,896	$ (569)	$ 6,223	$ 1,039,925	$ 10,008
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	90,180			94,466	(5,348)	89,118	1,062
Distributions to noncontrolling interest	(1,308)						(1,308)
Equity Issuance Costs	(275)		(275)			(275)
Shares issued on stock options exercised, shares		80,319
Stock Issued During Period, Value, Stock Options Exercised	1	$ 1				1
Share-based compensation	1,930		1,930			1,930
Dividends declared, $1.54 per share	$ (95,795)			(95,795)		(95,795)
Balance, shares at Sep. 30, 2015	37,566,221	37,566,221
Balance, value at Sep. 30, 2015	$ 1,044,666	$ 376	$ 1,035,551	$ (1,898)	$ 875	$ 1,034,904	$ 9,762