Consolidated Statement Of Equity - 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]
Stockholders' Equity Attributable to Noncontrolling Interest	$ 9,168
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	77,320			77,320	(21,836)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	55,484					55,484
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	770						770
Comprehensive income	56,254
Distributions to noncontrolling interest	$ (866)						866
Stock Issued During Period, Shares, New Issues	714,666
Stock Issued During Period, Value, New Issues	$ 50,189	$ 8	50,181			50,189
Adjustments Related to Tax Withholding for Share-based Compensation	(822)		822			822
Shares issued on stock options exercised, shares		43,479
Stock Issued During Period, Value, Stock Options Exercised	1		1			1
Share-based compensation	1,230		1,230			1,230
Dividends declared, $1.54 per share	(69,803)			(69,803)		(69,803)
Balance, shares at Jun. 30, 2016		39,154,872
Balance, value at Jun. 30, 2016	$ 1,178,643	$ 392	1,135,726	27,379	6,074	1,169,571	9,072
Balance, shares at Mar. 31, 2016	39,154,872
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	$ 44,595
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	24,400
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	386
Comprehensive income	24,786
Balance, shares at Jun. 30, 2016		39,154,872
Balance, value at Jun. 30, 2016	1,178,643	$ 392	$ 1,135,726	$ 27,379	$ 6,074	$ 1,169,571	$ 9,072
Stockholders' Equity Attributable to Noncontrolling Interest	$ 9,072