Condensed Consolidated Statement Of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Parent [Member]	Common Stock [Member]	Capital In Excess Of Par Value [Member]	Cumulative Dividends In Excess Of Net Income [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Balance, value at Dec. 31, 2011 at Dec. 31, 2011	$ 443,485	$ 443,485	$ 278	$ 465,678	$ (29,652)	$ 7,181
Balance, shares at Dec. 31, 2011	27,751,208		27,751,208
Comprehensive income:
Net income	49,628				49,628
Other Comprehensive income:
Unrealized holding gain/(loss) arising during the period	567
Net gain recognized in other comprehensive income	(806)	48,822				(806)
Noncontrolling interest							10,964
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	48,822
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest	10,964
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			79,103
Proceeds from Stock Options Exercised	(2)	(2)		(2)
Share-based compensation	1,924	1,924	0	1,924	0	0
Cash Dividends:
Cash dividends to common stockholders	(54,782)	(54,782)	0	0	(54,782)	0
Balance, value at June 30, 2012 at Sep. 30, 2012	450,411	439,447	278	467,600	(34,806)	6,375	10,964
Balance, shares at Sep. 30, 2012	27,830,311		27,830,311
Balance, value at Dec. 31, 2011 at Jun. 30, 2012
Comprehensive income:
Net income	14,351
Other Comprehensive income:
Unrealized holding gain/(loss) arising during the period	(1,336)
Net gain recognized in other comprehensive income	(1,772)
Noncontrolling interest							10,964
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	12,579
Balance, value at June 30, 2012 at Sep. 30, 2012	$ 450,411						$ 10,964
Balance, shares at Sep. 30, 2012	27,830,311