Earnings Per Share (Calculation of Basic and Diluted EPS) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 9,195	$ 11,787	$ 16,433	$ 18,737
Average Common Shares:
Basic (weighted-average outstanding shares)	12,097	12,044	12,090	12,025
Dilutive potential common shares from stock options, shares	179	156	183	154
Diluted (weighted-average outstanding shares)	12,276	12,200	12,273	12,179
Basic earnings per share (in dollars per share)	$ 0.76	$ 0.98	$ 1.36	$ 1.56
Diluted earnings per share (in dollars per share)	$ 0.75	$ 0.97	$ 1.34	$ 1.54