Subsequent Event - Supplemental Pro Forma Financial Information (Details) (Valley Green Bank [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Valley Green Bank [Member]
Business Acquisition [Line Items]
Net interest income	$ 92,356	$ 89,897
Noninterest income	49,325	47,550
Noninterest expense	98,792	90,456
Net income	$ 27,503	$ 26,557
Earnings per share
Basic (in dollars per share)	$ 1.37	$ 1.30
Diluted (in dollars per share)	$ 1.37	$ 1.30