Significant Accounting Policies (Business Combinations) (Details) (USD $)	0 Months Ended
	Oct. 31, 2014	Dec. 07, 2012 Branches	Apr. 30, 2010	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill acquired				$ 180,128,000	$ 120,164,000
Northwestern Bancorp [Member]
Business Acquisition [Line Items]
Acquisition purchase price	121,008,000
Goodwill acquired	59,964,000
Intangibles acquired	12,891,000
Independent Bank [Member]
Business Acquisition [Line Items]
Number of branches acquired (branches)		21
Deposits acquired		404,000,000
Loans acquired		44,000,000
Acquisition purchase price		8,100,000
Premium paid on deposits purchased		11,500,000
Premium paid as a percent of deposits purchased (percent)		2.85%
Discount on loans purchased (percent)		1.75%
Goodwill acquired		6,800,000
Intangibles acquired		5,600,000
OAK [Member]
Business Acquisition [Line Items]
Acquisition purchase price			83,700,000
Goodwill acquired			43,500,000
Intangibles acquired			$ 9,800,000