Equity and Noncontrolling Interest (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Beginning Balance	$ 289,676	$ 261,357
Net Income	14,191	13,112
Amounts reported in other comprehensive income (loss)	(25)	5,279
Dividends, Common Stock	(3,219)	(3,114)
Share Issuance and Equity-Based Compensation Plans	981	(102)
Excess Tax Benefit From Stock Option Exercises	369	1,252
Ending Balance	301,973	277,784
Common Stock Member
Beginning Balance	13,095	12,912
Net Income	0	0
Amounts reported in other comprehensive income (loss)	0	0
Dividends, Common Stock	0	0
Share Issuance and Equity-Based Compensation Plans	45	39
Excess Tax Benefit From Stock Option Exercises	0	0
Ending Balance	13,140	12,951
Additional Paid-in Capital [Member]
Beginning Balance	94,470	89,725
Net Income	0	0
Amounts reported in other comprehensive income (loss)	0	0
Dividends, Common Stock	0	0
Share Issuance and Equity-Based Compensation Plans	936	(141)
Excess Tax Benefit From Stock Option Exercises	369	1,252
Ending Balance	95,775	90,836
Retained Earnings [Member]
Beginning Balance	215,390	180,710
Net Income	13,619	12,365
Amounts reported in other comprehensive income (loss)	0	0
Dividends, Common Stock	(3,219)	(3,114)
Share Issuance and Equity-Based Compensation Plans	0	0
Excess Tax Benefit From Stock Option Exercises	0	0
Ending Balance	225,790	189,961
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	(41,855)	(28,967)
Net Income	0	0
Amounts reported in other comprehensive income (loss)	108	4,988
Dividends, Common Stock	0	0
Share Issuance and Equity-Based Compensation Plans	0	0
Excess Tax Benefit From Stock Option Exercises	0	0
Ending Balance	(41,747)	(23,979)
Noncontrolling Interest [Member]
Beginning Balance	8,576	6,977
Net Income	572	747
Amounts reported in other comprehensive income (loss)	(133)	291
Dividends, Common Stock	0	0
Share Issuance and Equity-Based Compensation Plans	0	0
Excess Tax Benefit From Stock Option Exercises	0	0
Ending Balance	$ 9,015	$ 8,015