Deposits - Summary of Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Weighted Average Rate
NOW (as a percent)	0.06%	0.06%
Money market (as a percent)	0.26%	0.24%
Savings (as a percent)	0.05%	0.05%
Total core deposits (as a percent)	0.12%	0.11%
Certificates of deposit (as a percent)	1.16%	1.47%
Total deposits (as a percent)	0.35%	0.50%
Balance
NOW	$ 1,415,430	$ 1,331,345
Non-interest bearing NOW and demand deposit	998,393	867,432
Money market	2,560,204	2,373,484
Savings	2,137,818	2,237,142
Total core deposits	7,111,845	6,809,403
Certificates of deposit	1,994,182	2,695,506
Total deposits	$ 9,106,027	$ 9,504,909
Percent of Total:
NOW (as a percent)	15.54%	14.01%
Non-interest bearing NOW and demand deposit (as a percent)	10.96%	9.13%
Money market (as a percent)	28.12%	24.96%
Savings (as a percent)	23.48%	23.54%
Total core deposits (as a percent)	78.10%	71.64%
Certificates of deposit (as a percent)	21.90%	28.36%
Total deposits (as a percent)	100.00%	100.00%