Earnings Per Share (EPS Components) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Summary of earnings per share
Net income	$ 15,738	$ 14,655	$ 43,867	$ 39,665
Weighted Average Shares (in shares)
BASIC SHARES	23,911,678	22,946,308	23,876,391	22,886,521
EFFECT OF DILUTIVE SECURITIES	90,685	100,806	95,320	72,799
DILUTIVE SHARES	24,002,363	23,047,114	23,971,711	22,959,320
NET INCOME PER SHARE (in dollars per share)
BASIC EPS	$ 0.66	$ 0.64	$ 1.84	$ 1.73
EFFECT OF DILUTIVE SECURITIES			$ (0.01)
DILUTIVE EPS	$ 0.66	$ 0.64	$ 1.83	$ 1.73