Equity and Noncontrolling Interest (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Beginning Balance	$ 301,973	$ 277,784	$ 289,676	$ 261,357
Net Income	16,675	11,738	30,866	24,850
Amounts reported in other comprehensive income (loss)	(4,336)	(6,982)	(4,361)	(1,703)
Dividends, Common Stock	(3,293)	(3,188)	(6,512)	(6,302)
Dividends Paid to Noncontrolling Interest		(30)		(30)
Share Issuance and Equity-Based Compensation Plans	1,255	1,255	2,236	1,153
Excess Tax Benefit From Stock Option Exercises	83	168	452	1,420
Ending Balance	312,357	280,745	312,357	280,745
Common Stock Member
Beginning Balance	13,140	12,951	13,095	12,912
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends, Common Stock	0	0	0	0
Dividends Paid to Noncontrolling Interest		0		0
Share Issuance and Equity-Based Compensation Plans	28	60	73	99
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	13,168	13,011	13,168	13,011
Additional Paid-in Capital [Member]
Beginning Balance	95,775	90,836	94,470	89,725
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends, Common Stock	0	0	0	0
Dividends Paid to Noncontrolling Interest		0		0
Share Issuance and Equity-Based Compensation Plans	1,227	1,195	2,163	1,054
Excess Tax Benefit From Stock Option Exercises	83	168	452	1,420
Ending Balance	97,085	92,199	97,085	92,199
Retained Earnings [Member]
Beginning Balance	225,790	189,961	215,390	180,710
Net Income	16,083	11,108	29,702	23,473
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends, Common Stock	(3,293)	(3,188)	(6,512)	(6,302)
Dividends Paid to Noncontrolling Interest		0		0
Share Issuance and Equity-Based Compensation Plans	0	0	0	0
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	238,580	197,881	238,580	197,881
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	(41,747)	(23,979)	(41,855)	(28,967)
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	(3,505)	(6,557)	(3,397)	(1,569)
Dividends, Common Stock	0	0	0	0
Dividends Paid to Noncontrolling Interest		0		0
Share Issuance and Equity-Based Compensation Plans	0	0	0	0
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	(45,252)	(30,536)	(45,252)	(30,536)
Noncontrolling Interest [Member]
Beginning Balance	9,015	8,015	8,576	6,977
Net Income	592	630	1,164	1,377
Amounts reported in other comprehensive income (loss)	(831)	(425)	(964)	(134)
Dividends, Common Stock	0	0	0	0
Dividends Paid to Noncontrolling Interest		(30)		(30)
Share Issuance and Equity-Based Compensation Plans	0	0	0	0
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	$ 8,776	$ 8,190	$ 8,776	$ 8,190