Borrowings and Subordinated Debentures (Details 1) $ in Thousands, € in Millions		6 Months Ended
		Jun. 30, 2017 USD ($)	Jun. 30, 2017 EUR (€)	Dec. 31, 2016 USD ($)
Subordinated Borrowing [Line Items]
Amount		$ 541,205		$ 538,973
Unamortized discount	[1]	(95,462)		(98,229)
Net subordinated debentures		445,743		440,744
Subordinated Debt Trust V Due September 2033
Subordinated Borrowing [Line Items]
Amount		$ 10,310		$ 10,310
Rate		4.37%	4.37%	4.09%
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		4.30%	4.30%	4.01%
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		4.22%	4.22%	3.95%
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		3.92%	3.92%	3.64%
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		2.94%	2.94%	2.65%
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		2.85%	2.85%	2.56%
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		2.80%	2.80%	2.51%
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		3.20%	3.20%	2.91%
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		3.12%	3.12%	2.84%
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		3.12%	3.12%	2.84%
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		3.12%	3.12%	2.84%
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	[2]	$ 29,417		$ 27,185
Rate		1.72%	1.72%	1.74%
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		3.12%	3.12%	2.84%
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		3.12%	3.12%	2.84%
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		3.12%	3.12%	2.84%
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)		4.37%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust VI Due September 2033
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		4.30%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust CII Due September 2033
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		4.22%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust VII Due April 2034
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.92%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust CIII Due September 2035
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.94%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust FCCI Due March 2037
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.85%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust FCBI Due December 2035
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.80%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Five Series One
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.20%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Five Series Two
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.12%
London Interbank Offered Rate (LIBOR) | Two Thousand Six One Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.12%
London Interbank Offered Rate (LIBOR) | Two Thousand Six Two Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.12%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Six Series Four
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.12%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Six Series Five
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.12%
London Interbank Offered Rate (LIBOR) | Two Thousand Seven One Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.12%
Euribor Future | Trust Preferred Securities Two Thousand Six Series Three
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.72%

[1] There was only one asset-backed security at June 30, 2017.

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