Equity and Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Beginning Balance	$ 421,975	$ 391,526	$ 412,606	$ 381,243
Net Income	12,341	15,405	19,955	28,749
Amounts reported in other comprehensive income (loss)	9,074	(3,941)	15,040	1,435
Repurchases of common stock	0	0	0	(5,859)
Dividends, Common Stock	(4,724)	(4,572)	(9,311)	(8,799)
Share Issuance and Equity-Based Compensation Plans	928	1,783	1,304	3,328
Excess Tax Benefit From Stock Option Exercises	0	32	0	136
Ending Balance	439,594	400,233	439,594	400,233
Common Stock [Member]
Beginning Balance	13,291	13,236	13,278	13,288
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Repurchases of common stock	0	0	0	(84)
Dividends, Common Stock	0	0	0	0
Share Issuance and Equity-Based Compensation Plans	19	14	32	46
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	13,310	13,250	13,310	13,250
Additional Paid-in Capital [Member]
Beginning Balance	112,838	107,950	112,475	106,333
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
Share Issuance and Equity-Based Compensation Plans	909	1,769	1,272	3,282
Excess Tax Benefit From Stock Option Exercises	0	32	0	136
Ending Balance	113,747	109,751	113,747	109,751
Retained Earnings [Member]
Beginning Balance	366,819	329,684	364,414	326,740
Net Income	11,906	15,015	18,898	27,961
Amounts reported in other comprehensive income (loss)	0	0	0	0
Repurchases of common stock	0	0	0	(5,775)
Dividends, Common Stock	(4,724)	(4,572)	(9,311)	(8,799)
Share Issuance and Equity-Based Compensation Plans	0	0	0	0
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	374,001	340,127	374,001	340,127
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	(81,961)	(68,002)	(87,407)	(73,316)
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	9,023	(3,788)	14,469	1,526
Repurchases of common stock	0	0	0	0
Dividends, Common Stock	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	(72,938)	(71,790)	(72,938)	(71,790)
Noncontrolling Interest [Member]
Beginning Balance	10,988	8,658	9,846	8,198
Net Income	435	390	1,057	788
Amounts reported in other comprehensive income (loss)	51	(153)	571	(91)
Repurchases of common stock	0	0	0	0
Dividends, Common Stock	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	$ 11,474	$ 8,895	$ 11,474	$ 8,895