Equity and Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Beginning Balance	$ 400,233	$ 378,526	$ 381,243	$ 365,135
Net Income	16,351	14,835	45,100	40,854
Amounts reported in other comprehensive income (loss)	(60)	(11,361)	1,375	(17,820)
Repurchases of common stock	0	(3,359)	(5,859)	(4,989)
Dividends, Common Stock	(4,575)	(4,256)	(13,374)	(12,525)
Acquisition of Noncontrolling Interest	40	0	40	0
Disposition of Noncontrolling Interest	0	0	0	(351)
Share Issuance and Equity-Based Compensation Plans	1,678	1,744	5,006	5,447
Excess Tax Benefit From Stock Option Exercises	31	22	167	400
Ending Balance	413,698	376,151	413,698	376,151
Common Stock [Member]
Beginning Balance	13,250	13,337	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	(40)	(84)	(59)
Dividends, Common Stock	0	0	0	0
Disposition of Noncontrolling Interest	0	0	0	0
Share Issuance and Equity-Based Compensation Plans	7	9	53	64
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	13,257	13,306	13,257	13,306
Additional Paid-in Capital [Member]
Beginning Balance	109,751	103,082	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	1,671	1,735	4,953	5,383
Excess Tax Benefit From Stock Option Exercises	31	22	167	400
Ending Balance	111,453	104,839	111,453	104,839
Retained Earnings [Member]
Beginning Balance	340,127	315,060	326,740	299,524
Net Income	16,008	14,371	43,969	39,787
Amounts reported in other comprehensive income (loss)	0	0	0	0
Repurchases of common stock	0	(3,319)	(5,775)	(4,930)
Dividends, Common Stock	(4,575)	(4,256)	(13,374)	(12,525)
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	351,560	321,856	351,560	321,856
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	(71,790)	(60,771)	(73,316)	(54,406)
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	(237)	(10,994)	1,289	(17,359)
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	(72,027)	(71,765)	(72,027)	(71,765)
Noncontrolling Interest [Member]
Beginning Balance	8,895	7,818	8,198	7,660
Net Income	343	464	1,131	1,067
Amounts reported in other comprehensive income (loss)	177	(367)	86	(461)
Repurchases of common stock	0	0	0	0
Dividends, Common Stock	0	0	0	0
Acquisition of Noncontrolling Interest	40	0	40	0
Disposition of Noncontrolling Interest	0	0	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	$ 9,455	$ 7,915	$ 9,455	$ 7,915