Earnings Per Share (EPS Components) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Summary of earnings per share
Net income	$ 18,594	$ 15,738	$ 45,505	$ 43,867
Weighted Average Shares (in shares)
BASIC SHARES	26,200,621	23,911,678	25,774,571	23,876,391
EFFECT OF DILUTIVE SECURITIES	63,493	90,685	72,921	95,320
DILUTIVE SHARES	26,264,114	24,002,363	25,847,492	23,971,711
NET INCOME PER SHARE (in dollars per share)
BASIC EPS	$ 0.71	$ 0.66	$ 1.77	$ 1.84
EFFECT OF DILUTIVE SECURITIES	0.00	0.00	(0.01)	(0.01)
DILUTIVE EPS	$ 0.71	$ 0.66	$ 1.76	$ 1.83