Deposits Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Interest checking deposits	$ 2,711,250	$ 1,462,305
Money market deposits	4,890,567	4,865,961
Savings deposits	690,353	711,039
Time deposits $250,000 and under	1,709,980	1,758,434
Time deposits over $250,000	355,342	413,856
Total interest-bearing deposits	$ 10,357,492	$ 9,211,595