Commitments and Contingencies (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Loan commitments to extend credit	$ 4,156,147	$ 3,580,655
Standby letters of credit	204,616	210,292
Commitments to purchase equipment being acquired for lease to others	0	6,663
Total	$ 4,360,763	$ 3,797,610