Investment Securities (Gains and losses by category) (Details) - USD ($)	6 Months Ended	12 Months Ended
Jun. 30, 2017	Dec. 31, 2016
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month	$ 266,288,000	$ 335,079,000
Available for sale - Amortized cost - more than 12 month	38,342,000	38,563,000
Total Available for Sale Amortization cost	304,630,000	373,642,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month	3,064,000	5,723,000
Available for sale - Unrealized Loss - more than 12 month	708,000	1,400,000
Total Available for Sale Unrealized Loss	3,772,000	7,123,000
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month	263,224,000	329,356,000
Available-for-sale, Fair Value - more than 12 month	37,634,000	37,163,000
Total Available for Sale Fair Value	300,858,000	366,519,000
Continuous Unrealized Loss Position Amortized Cost [Abstract]
Held to Maturity - Amortized cost - less than 12 month	471,100,000	525,258,000
Held to Maturity - Amortized cost - more than 12 month	6,753,000
Held to Maturity - Amortized Cost	477,853,000	525,258,000
Held To Maturity Securities, Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Held to Maturity- Unrealized Loss - less than 12 month	5,860,000	7,266,000
Held to Maturity- Unrealized Loss - more than 12 month	164,000
Held to Maturity- Unrealized Loss	6,024,000	7,266,000
Held To Maturity Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Held-to-Maturity - Fair Value - less than 12 Month	465,240,000	517,992,000
Held-to-Maturity - Fair Value - more than 12 Month	6,589,000
Held to Maturity - Fair Value	471,829,000	517,992,000
Investment Securities Continuous Unrealized Loss Position [Abstract]
Investment Securities - Amortized Cost	782,483,000	898,900,000
Investment Securities - Unrealized Loss	9,796,000	14,389,000
Investment Securities - Fair Value	772,687,000	884,511,000
CMO's issued by us government sponsored agencies at loss
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month	61,115,000	67,777,000
Available for sale - Amortized cost - more than 12 month	30,309,000	33,883,000
Total Available for Sale Amortization cost	91,424,000	101,660,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month	736,000	1,430,000
Available for sale - Unrealized Loss - more than 12 month	342,000	793,000
Total Available for Sale Unrealized Loss	1,078,000	2,223,000
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month	60,379,000	66,347,000
Available-for-sale, Fair Value - more than 12 month	29,967,000	33,090,000
Total Available for Sale Fair Value	90,346,000	99,437,000
Obligation of Puerto Rico Government and public instrumentalities at loss
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - more than 12 month	4,680,000	4,680,000
Total Available for Sale Amortization cost	4,680,000	4,680,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - more than 12 month	339,000	607,000
Total Available for Sale Unrealized Loss	339,000	607,000
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available-for-sale, Fair Value - more than 12 month	4,341,000	4,073,000
Total Available for Sale Fair Value	4,341,000	4,073,000
FNMA and FHLMC [Member]
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month	164,473,000	184,782,000
Total Available for Sale Amortization cost	164,473,000	184,782,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month	1,797,000	3,036,000
Total Available for Sale Unrealized Loss	1,797,000	3,036,000
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month	162,676,000	181,746,000
Total Available for Sale Fair Value	162,676,000	181,746,000
Continuous Unrealized Loss Position Amortized Cost [Abstract]
Held to Maturity - Amortized cost - less than 12 month	471,100,000	525,258,000
Held to Maturity - Amortized cost - more than 12 month	6,753,000
Held to Maturity - Amortized Cost	477,853,000	525,258,000
Held To Maturity Securities, Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Held to Maturity- Unrealized Loss - less than 12 month	5,860,000	7,266,000
Held to Maturity- Unrealized Loss - more than 12 month	164,000
Held to Maturity- Unrealized Loss	6,024,000	7,266,000
Held To Maturity Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Held-to-Maturity - Fair Value - less than 12 Month	465,240,000	517,992,000
Held-to-Maturity - Fair Value - more than 12 Month	6,589,000
Held to Maturity - Fair Value	471,829,000	517,992,000
Government National Mortgage Association Certificates and Obligations (GNMA) [Member]
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month	30,437,000	29,445,000
Total Available for Sale Amortization cost	30,437,000	29,445,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month	487,000	620,000
Total Available for Sale Unrealized Loss	487,000	620,000
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month	29,950,000	28,825,000
Total Available for Sale Fair Value	29,950,000	28,825,000
Obligation of US Government sponsored agencies at loss [Member]
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month		3,903,000
Available for sale - Amortized cost - more than 12 month	3,353,000
Total Available for Sale Amortization cost	3,353,000	3,903,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month		618,000
Available for sale - Unrealized Loss - more than 12 month	27,000
Total Available for Sale Unrealized Loss	27,000	618,000
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month		3,884,000
Available-for-sale, Fair Value - more than 12 month	3,326,000
Total Available for Sale Fair Value	3,326,000	3,884,000
US Treasury Securities at loss
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month	10,263,000	49,172,000
Total Available for Sale Amortization cost	10,263,000	49,172,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month	44,000	618,000
Total Available for Sale Unrealized Loss	44,000	618,000
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month	10,219,000	48,554,000
Total Available for Sale Fair Value	$ 10,219,000	$ 48,554,000

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Amount of unrealized loss on investments in available-for-sale securities that have been in a loss position for less than twelve months.

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