Fair Value (Details) - Financial Instruments - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets:
Cash and due from banks	$ 125,279	$ 117,315
Interest-bearing deposits in other banks	822,264	488,947
Securities held-to-maturity, at amortized cost	23,723	26,555
FHLB and FRB stock	38,748	37,558
Loans	6,853,199	6,664,159
Investment in BOLI	208,666	206,498
Liabilities:
Deposits	8,296,450	7,887,758
Borrowed funds	169,943	137,994
Senior and subordinated debt	201,123	200,869
Level 1
Assets:
Cash and due from banks	125,279	117,315
Liabilities:
Senior and subordinated debt	207,045	209,035
Level 2
Assets:
Interest-bearing deposits in other banks	822,264	488,947
Securities held-to-maturity, at amortized cost	23,708	27,670
FHLB and FRB stock	38,748	37,558
Liabilities:
Deposits	8,295,488	7,879,413
Borrowed funds	169,942	137,994
Accrued interest payable	5,124	2,324
Level 3
Assets:
Loans	6,770,861	6,536,248
Investment in BOLI	208,666	206,498
Accrued interest receivable	27,897	27,506
Other interest-earning assets	2,357	3,799
Carrying Amount | Level 1
Assets:
Cash and due from banks	125,279	117,315
Liabilities:
Senior and subordinated debt	201,123	200,869
Carrying Amount | Level 2
Assets:
Interest-bearing deposits in other banks	822,264	488,947
Securities held-to-maturity, at amortized cost	23,723	26,555
FHLB and FRB stock	38,748	37,558
Liabilities:
Deposits	8,296,450	7,887,758
Borrowed funds	169,943	137,994
Accrued interest payable	5,124	2,324
Carrying Amount | Level 3
Assets:
Loans	6,859,305	6,672,611
Investment in BOLI	208,666	206,498
Accrued interest receivable	27,897	27,506
Other interest-earning assets	$ 2,357	$ 3,799