Commitments and Contingencies (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Loan commitments to extend credit	$ 2,022,046	$ 1,921,067
Standby letters of credit	104,073	88,495
Commitments to purchase equipment being acquired for lease to others	6,935	12,839
Total	$ 2,133,054	$ 2,022,401