Condensed Parent Company Financial Statements (Details) - Statements of Financial Condition (Parent Company Only) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and due from banks	$ 155,055	$ 114,587
Other assets	278,271	178,463
Total assets	11,422,555	9,732,676
Liabilities and Equity [Abstract]
Senior and subordinated debt	194,603	201,208
Accrued interest payable and other liabilities	263,261	122,366
Stockholders' equity	1,257,080	1,146,268	$ 1,100,775	$ 1,001,442
Total liabilities and stockholders' equity	11,422,555	9,732,676
Parent Company
Assets
Cash and due from banks	140,217	119,693
Investments in and advances to subsidiaries	1,279,065	1,194,173
Other assets	139,060	63,337
Total assets	1,558,342	1,377,203
Liabilities and Equity [Abstract]
Senior and subordinated debt	194,603	201,208
Accrued interest payable and other liabilities	106,659	29,727
Stockholders' equity	1,257,080	1,146,268
Total liabilities and stockholders' equity	$ 1,558,342	$ 1,377,203