Borrowings and Subordinated Debentures (Details 1) $ in Thousands, € in Millions		3 Months Ended
		Mar. 31, 2019 USD ($)	Mar. 31, 2019 EUR (€)	Dec. 31, 2018 USD ($)
Subordinated Borrowing [Line Items]
Amount		$ 540,702		$ 541,344
Rate		2.58%	2.58%	2.56%
Unamortized discount		$ (86,244)		$ (87,498)
Net subordinated debentures		454,458		453,846
Subordinated Debt Trust V Due September 2033
Subordinated Borrowing [Line Items]
Amount		$ 10,310		$ 10,310
Rate		5.71%	5.71%	5.89%
Date Issued		Aug. 15, 2003
Maturity Date		Sep. 17, 2033
Description of variable rate basis		3-month LIBOR + 3.10
Subordinated Debt Trust VI Due September 2033
Subordinated Borrowing [Line Items]
Amount		$ 10,310		$ 10,310
Rate		5.66%	5.66%	5.84%
Date Issued		Sep. 03, 2003
Maturity Date		Sep. 15, 2033
Description of variable rate basis		3-month LIBOR + 3.05
Subordinated Debt Trust CII Due September 2033
Subordinated Borrowing [Line Items]
Amount		$ 5,155		$ 5,155
Rate		5.56%	5.56%	5.74%
Date Issued		Sep. 17, 2003
Maturity Date		Sep. 17, 2033
Description of variable rate basis		3-month LIBOR + 2.95
Subordinated Debt Trust VII Due April 2034
Subordinated Borrowing [Line Items]
Amount		$ 61,856		$ 61,856
Rate		5.50%	5.50%	5.27%
Date Issued		Feb. 05, 2004
Maturity Date		Apr. 23, 2034
Description of variable rate basis		3-month LIBOR + 2.75
Subordinated Debt Trust CIII Due September 2035
Subordinated Borrowing [Line Items]
Amount		$ 20,619		$ 20,619
Rate		4.30%	4.30%	4.48%
Date Issued		Aug. 15, 2005
Maturity Date		Sep. 15, 2035
Description of variable rate basis		3-month LIBOR + 1.69
Subordinated Debt Trust FCCI Due March 2037
Subordinated Borrowing [Line Items]
Amount		$ 16,495		$ 16,495
Rate		4.21%	4.21%	4.39%
Date Issued		Jan. 25, 2007
Maturity Date		Mar. 15, 2037
Description of variable rate basis		3-month LIBOR + 1.60
Subordinated Debt Trust FCBI Due December 2035
Subordinated Borrowing [Line Items]
Amount		$ 10,310		$ 10,310
Rate		4.16%	4.16%	4.34%
Date Issued		Sep. 30, 2005
Maturity Date		Dec. 15, 2035
Description of variable rate basis		3-month LIBOR + 1.55
Trust Preferred Securities Two Thousand Five Series One
Subordinated Borrowing [Line Items]
Amount		$ 82,475		$ 82,475
Rate		4.56%	4.56%	4.74%
Date Issued		Nov. 21, 2005
Maturity Date		Dec. 15, 2035
Description of variable rate basis		3-month LIBOR + 1.95
Trust Preferred Securities Two Thousand Five Series Two
Subordinated Borrowing [Line Items]
Amount		$ 128,866		$ 128,866
Rate		4.70%	4.70%	4.47%
Date Issued		Dec. 14, 2005
Maturity Date		Jan. 30, 2036
Description of variable rate basis		3-month LIBOR + 1.95
Two Thousand Six One Term Debt Securitization
Subordinated Borrowing [Line Items]
Amount		$ 51,545		$ 51,545
Rate		4.70%	4.70%	4.47%
Date Issued		Feb. 22, 2006
Maturity Date		Apr. 30, 2036
Description of variable rate basis		3-month LIBOR + 1.95
Two Thousand Six Two Term Debt Securitization
Subordinated Borrowing [Line Items]
Amount		$ 51,550		$ 51,550
Rate		4.70%	4.70%	4.47%
Date Issued		Sep. 27, 2006
Maturity Date		Oct. 30, 2036
Description of variable rate basis		3-month LIBOR + 1.95
Trust Preferred Securities Two Thousand Six Series Three
Subordinated Borrowing [Line Items]
Amount	[1]	$ 28,914		$ 29,556
Rate		1.74%	1.74%	1.73%
Date Issued		Sep. 29, 2006
Maturity Date		Oct. 30, 2036
Denomination value | €			€ 25.8
Description of variable rate basis		3-month EURIBOR + 2.05
Trust Preferred Securities Two Thousand Six Series Four
Subordinated Borrowing [Line Items]
Amount		$ 16,470		$ 16,470
Rate		4.70%	4.70%	4.47%
Date Issued		Dec. 05, 2006
Maturity Date		Jan. 30, 2037
Description of variable rate basis		3-month LIBOR + 1.95
Trust Preferred Securities Two Thousand Six Series Five
Subordinated Borrowing [Line Items]
Amount		$ 6,650		$ 6,650
Rate		4.70%	4.70%	4.47%
Date Issued		Dec. 19, 2006
Maturity Date		Jan. 30, 2037
Description of variable rate basis		3-month LIBOR + 1.95
Two Thousand Seven One Term Debt Securitization
Subordinated Borrowing [Line Items]
Amount		$ 39,177		$ 39,177
Rate		4.70%	4.70%	4.47%
Date Issued		Jun. 13, 2007
Maturity Date		Jul. 30, 2037
Description of variable rate basis		3-month LIBOR + 1.95
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust V Due September 2033
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.10%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust VI Due September 2033
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.05%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust CII Due September 2033
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.95%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust VII Due April 2034
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.75%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust CIII Due September 2035
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.69%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust FCCI Due March 2037
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.60%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust FCBI Due December 2035
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.55%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Five Series One
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Five Series Two
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Two Thousand Six One Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Two Thousand Six Two Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Six Series Four
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Six Series Five
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Two Thousand Seven One Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
Euribor Rate | Trust Preferred Securities Two Thousand Six Series Three
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.05%

[1] Denomination is in Euros with a value of €25.8 million.