Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deposits, by Type [Abstract]
Noninterest-bearing demand	$ 1,934,583	$ 1,591,661
Interest-bearing demand	1,870,197	1,428,941
Savings	2,004,575	1,720,422
Time deposits over $100,000	701,830	557,476
Other time deposits	945,582	780,471
Total deposits	7,456,767	6,078,971
Maturities of Time Deposits [Abstract]
Time deposit maturities, one year or less	904,000
Time deposits maturities, after next twelve months	743,000
Time deposit maturities, 2017	395,000
Time deposit maturities, 2018	139,000
Time deposit maturities, 2019	88,000
Time deposit maturities, 2020	118,000
Time Deposit Maturities, 2021 and beyond	3,000
Demand deposit overdrafts	3,000	4,300
Time Deposits, $250,000 or More	$ 364,000	$ 249,000