Equity and Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Beginning Balance	$ 391,526	$ 365,129	$ 381,243	$ 365,135
Net Income	15,405	15,412	28,749	26,019
Amounts reported in other comprehensive income (loss)	(3,941)	2,076	1,435	(6,459)
Repurchases of common stock	0	(1,630)	(5,859)	(1,630)
Dividends, Common Stock	(4,572)	(4,269)	(8,799)	(8,269)
Disposition of Noncontrolling Interest	0	(351)	0	(351)
Share Issuance and Equity-Based Compensation Plans	1,783	2,068	3,328	3,703
Excess Tax Benefit From Stock Option Exercises	32	91	136	378
Ending Balance	400,233	378,526	400,233	378,526
Common Stock [Member]
Beginning Balance	13,236	13,332	13,288	13,301
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Repurchases of common stock	0	(19)	(84)	(19)
Dividends, Common Stock	0	0	0	0
Disposition of Noncontrolling Interest	0	0	0	0
Share Issuance and Equity-Based Compensation Plans	14	24	46	55
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	13,250	13,337	13,250	13,337
Additional Paid-in Capital [Member]
Beginning Balance	107,950	100,947	106,333	99,056
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Repurchases of common stock	0	0	0	0
Dividends, Common Stock	0	0	0	0
Disposition of Noncontrolling Interest	0	0	0	0
Share Issuance and Equity-Based Compensation Plans	1,769	2,044	3,282	3,648
Excess Tax Benefit From Stock Option Exercises	32	91	136	378
Ending Balance	109,751	103,082	109,751	103,082
Retained Earnings [Member]
Beginning Balance	329,684	305,902	326,740	299,524
Net Income	15,015	15,038	27,961	25,416
Amounts reported in other comprehensive income (loss)	0	0	0	0
Repurchases of common stock	0	(1,611)	(5,775)	(1,611)
Dividends, Common Stock	(4,572)	(4,269)	(8,799)	(8,269)
Disposition of Noncontrolling Interest	0	0	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	340,127	315,060	340,127	315,060
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	(68,002)	(62,971)	(73,316)	(54,406)
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	(3,788)	2,200	1,526	(6,365)
Repurchases of common stock	0	0	0	0
Dividends, Common Stock	0	0	0	0
Disposition of Noncontrolling Interest	0	0	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	(71,790)	(60,771)	(71,790)	(60,771)
Noncontrolling Interest [Member]
Beginning Balance	8,658	7,919	8,198	7,660
Net Income	390	374	788	603
Amounts reported in other comprehensive income (loss)	(153)	(124)	(91)	(94)
Repurchases of common stock	0	0	0	0
Dividends, Common Stock	0	0	0	0
Disposition of Noncontrolling Interest	0	(351)	0	(351)
Share Issuance and Equity-Based Compensation Plans	0	0	0	0
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	$ 8,895	$ 7,818	$ 8,895	$ 7,818