Share-Based Compensation - Components of Share Based Compensation Awards (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax compensation expense	$ 517	$ 505
Income tax expense (benefit)	(169)	(164)
Total share-based compensation expense, net of income taxes	348	341
Stock and ESPP Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax compensation expense	27	44
Income tax expense (benefit)	(1)	(3)
Total share-based compensation expense, net of income taxes	26	41
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax compensation expense	490	461
Income tax expense (benefit)	(168)	(161)
Total share-based compensation expense, net of income taxes	$ 322	$ 300