Earnings per Share (Reconciliation between Basic and Diluted Earnings per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Net income for basic and diluted earnings per share	$ 15,417	$ 17,344
Basic weighted average shares outstanding	38,318	37,168
Dilutive effect of stock options and restricted stock awards	282	1,611
Diluted weighted average shares outstanding	38,600	38,779
Basic earnings per common share	$ 0.40	$ 0.47
Diluted earnings per common share	$ 0.40	$ 0.45