Deposits (Summary of Deposits) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deposits [Abstract]
Non-interest bearing, Balance	$ 4,836,420	$ 3,518,685
NOW and interest bearing demand deposits, Balance	2,390,217	2,236,089
Wealth management deposits, Balance	1,643,653	1,226,916
Money market, Balance	4,041,300	3,651,467
Savings, Balance	1,723,367	1,508,877
Time certificates of deposit, Balance	4,004,677	4,139,810
Total deposits	$ 18,639,634	$ 16,281,844
Non-interest bearing, Mix	26.00%	22.00%
NOW and interest bearing demand deposits, Mix	13.00%	14.00%
Wealth management deposits, Mix	9.00%	8.00%
Money market, Mix	22.00%	22.00%
Savings, Mix	9.00%	9.00%
Time certificates of deposit, Mix	21.00%	25.00%
Total deposits, Mix	100.00%	100.00%