Commitments and Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Loan commitments to extend credit	$ 4,166,703	$ 3,580,655
Standby letters of credit	211,398	210,292
Commitments to purchase equipment being acquired for lease to others	0	6,663
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 4,378,101	$ 3,797,610