Deposits - Maturity Distribution of Time Certificates of Deposits (Details) $ in Thousands	Jun. 30, 2016 USD ($)
Maturity distribution of time certificates of deposits
Three months or less	$ 1,613,390
Over three through six months	859,100
Over six through twelve months	688,595
One to two years	173,042
Two to three years	164,921
Three to four years	138,504
Four to five years	144,160
Thereafter	112
Total	3,781,824
$250,000 or More
Maturity distribution of time certificates of deposits
Three months or less	1,388,351
Over three through six months	620,086
Over six through twelve months	344,017
One to two years	87,773
Two to three years	37,174
Three to four years	32,048
Four to five years	48,558
Total	2,558,007
Under $250,000
Maturity distribution of time certificates of deposits
Three months or less	225,039
Over three through six months	239,014
Over six through twelve months	344,578
One to two years	85,269
Two to three years	127,747
Three to four years	106,456
Four to five years	95,602
Thereafter	112
Total	$ 1,223,817