Equity and Noncontrolling Interest (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Beginning Balance	$ 358,008	$ 301,973	$ 344,696	$ 289,676
Net Income	15,942	16,675	29,251	30,866
Amounts reported in other comprehensive income (loss)	1,423	(4,336)	3,312	(4,361)
Dividends, Common Stock	(3,973)	(3,293)	(7,281)	(6,512)
Distributions to Noncontrolling Affiliate Shareholders	(657)	0	(657)	0
Acqusition of Noncontrolling Interest	(7,577)	0	(7,577)	0
Share Issuance and Equity-Based Compensation Plans	1,516	1,255	2,699	2,236
Excess Tax Benefit From Stock Option Exercises	28	83	267	452
Ending Balance	364,710	312,357	364,710	312,357
Common Stock Member
Beginning Balance	13,227	13,140	13,196	13,095
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends, Common Stock	0	0	0	0
Distributions to Noncontrolling Affiliate Shareholders	0	0	0	0
Acqusition of Noncontrolling Interest	0	0	0	0
Share Issuance and Equity-Based Compensation Plans	15	28	46	73
Excess Tax Benefit From Stock Option Exercises	0	0	0	0
Ending Balance	13,242	13,168	13,242	13,168
Additional Paid-in Capital [Member]
Beginning Balance	100,429	95,775	99,038	94,470
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends, Common Stock	0	0	0	0
Distributions to Noncontrolling Affiliate Shareholders	0	0	0	0
Acqusition of Noncontrolling Interest	(6,450)	0	(6,450)	0
Share Issuance and Equity-Based Compensation Plans	1,501	1,227	2,653	2,163
Excess Tax Benefit From Stock Option Exercises	28	83	267	452
Ending Balance	95,508	97,085	95,508	97,085
Retained Earnings [Member]
Beginning Balance	267,707	225,790	258,285	215,390
Net Income	15,427	16,083	28,157	29,702
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends, Common Stock	(3,973)	(3,293)	(7,281)	(6,512)
Distributions to Noncontrolling Affiliate Shareholders	0	0	0	0
Acqusition 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	279,161	238,580	279,161	238,580
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	(33,015)	(41,747)	(34,700)	(41,855)
Net Income	0	0	0	0
Amounts reported in other comprehensive income (loss)	1,428	(3,505)	3,113	(3,397)
Dividends, Common Stock	0	0	0	0
Distributions to Noncontrolling Affiliate Shareholders	0	0	0	0
Acqusition 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	(31,587)	(45,252)	(31,587)	(45,252)
Noncontrolling Interest [Member]
Beginning Balance	9,660	9,015	8,877	8,576
Net Income	515	592	1,094	1,164
Amounts reported in other comprehensive income (loss)	(5)	(831)	199	(964)
Dividends, Common Stock	0	0	0	0
Distributions to Noncontrolling Affiliate Shareholders	(657)	0	(657)	0
Acqusition of Noncontrolling Interest	(1,127)	0	(1,127)	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	$ 8,386	$ 8,776	$ 8,386	$ 8,776