Shareholders' Equity and Stock Compensation (Narrative) (Details) - USD ($)		1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 18, 2014	Nov. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Shareholders Equity and Share-Based Payments [Line Items]
Number of securities called by each warrant	1.671
Warrant exercise price (usd per share)	$ 12.88
Shares issued from exercise of warrants							2,889,896
Common stock, shares authorized	400,000,000		400,000,000		400,000,000		400,000,000
Compensation cost			$ 3,100,000	$ 3,700,000	$ 10,700,000	$ 8,800,000
Total income tax benefit recognized related to stock-based compensation			1,200,000	1,400,000	3,900,000	3,400,000
Total intrinsic value of options exercised			47,000	241,000	512,000	3,100,000
Cash received from exercise of stock options			117,000	483,000	$ 877,000	6,700,000
Stock options granted					0
Income tax benefits received			700,000	469,000	$ 5,100,000	6,200,000
Net tax benefit from stock options exercised					544,000
Tax deficiency from stock options exercised						1,200,000
Restricted Stock Units (RSUs) [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Total unrecognized compensation cost related to nonvested stock awards			4,600,000		$ 4,600,000
Expected recognized over a weighted-average period, years					1 year 9 months 7 days
Restricted Shares [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Total fair value of restricted stock shares/units vested and released			1,600,000	615,000	$ 8,300,000	7,000,000
Total unrecognized compensation cost related to nonvested stock awards			10,100,000		$ 10,100,000
Expected recognized over a weighted-average period, years					1 year 4 months 6 days
Employee Stock Option [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Total unrecognized compensation cost related to nonvested stock awards			135,000		$ 135,000
Expected recognized over a weighted-average period, years					1 year 8 months 16 days
Restricted Stock Units (RSUs) [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Total fair value of restricted stock shares/units vested and released			430,000	363,000	$ 4,400,000	6,000,000
Employee Stock Option [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Cash received from exercise of stock options			$ 16	$ 239,000	$ 195,000	$ 4,500,000
Sterling Financial Corporation [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Shares issued from exercise of warrants		2,889,896
Value of shares issued from exercise of warrants		$ 6,600,000
Merger with Sterling Financial Corporation [Member] | Restricted Stock Units (RSUs) [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Conversion of stock, shares issued	994,214
Merger with Sterling Financial Corporation [Member] | Employee Stock Option [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Conversion of stock, shares issued	439,921
Merger with Sterling Financial Corporation [Member] | Common Stock [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Conversion of stock, shares issued	104,385,087
Merger with Sterling Financial Corporation [Member] | Warrant [Member]
Shareholders Equity and Share-Based Payments [Line Items]
Conversion of stock, shares converted	2,960,238