Deposits - Maturity Distribution of Time Certificates of Deposits (Details) $ in Thousands	Dec. 31, 2016 USD ($)
Maturity distribution of time certificates of deposits
Three months or less	$ 1,711,000
Over three through six months	743,275
Over six through twelve months	666,078
2018	173,960
2019	180,704
2020	122,683
2020	140,885
Thereafter	11
Total	3,738,596
Under $250,000
Maturity distribution of time certificates of deposits
Three months or less	172,846
Over three through six months	199,920
Over six through twelve months	396,636
2018	93,774
2019	139,366
2020	89,773
2020	100,008
Thereafter	11
Total	1,192,334
$250,000 or More
Maturity distribution of time certificates of deposits
Three months or less	1,538,154
Over three through six months	543,355
Over six through twelve months	269,442
2018	80,186
2019	41,338
2020	32,910
2020	40,877
Total	$ 2,546,262