Consolidated Statement Of Equity (USD $) In Thousands, except Share data, unless otherwise specified	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, value at Dec. 31, 2013	$ 777,160	$ 330	$ 753,635	$ 3,043	$ 9,538	$ 766,546	$ 10,614
Balance, shares at Dec. 31, 2013	33,051,176	33,051,176
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	45,920			48,828	(3,514)	45,314	606
Distributions to noncontrolling interest	(865)						(865)
Shares issued on stock options exercised, shares		3,423
Stock Issued During Period, Value, Stock Options Exercised	1	1	0			1
Share-based compensation	1,573		1,573			1,573
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	7,495		7,495			7,495
Dividends declared, $1.54 per share	(50,902)			(50,902)		(50,902)
Balance, value at Jun. 30, 2014	$ 780,382	$ 331	$ 762,703	$ 969	$ 6,024	$ 770,027	$ 10,355
Balance, shares at Jun. 30, 2014		33,054,599