Derivatives and Hedging Activity - Designated and Non-Designated Hedges (Details) - 3 months ended Mar. 31, 2016 € in Thousands, £ in Thousands, SEK in Thousands, NOK in Thousands, DKK in Thousands, $ in Thousands	NOK instrument item	GBP (£) instrument item	SEK instrument item	DKK instrument item	EUR (€) instrument item	USD ($) instrument item
Derivatives
Number of contracts	203	203	203	203	203	203
Foreign exchange contracts | GBP | Sell
Derivatives
Number of contracts	61	61	61	61	61	61
Aggregate notional amount | £		£ 239,773
Foreign exchange contracts | EUR | Buy
Derivatives
Number of contracts	1	1	1	1	1	1
Aggregate notional amount | €					€ 76
Foreign exchange contracts | EUR | Sell
Derivatives
Number of contracts	82	82	82	82	82	82
Aggregate notional amount | €					€ 343,717
Foreign exchange contracts | EUR | Sell | Ireland Portfolio
Derivatives
Number of contracts	51	51	51	51	51	51
Aggregate notional amount | €					€ 249,400
Foreign exchange contracts | SEK | Buy
Derivatives
Number of contracts	1	1	1	1	1	1
Aggregate notional amount | SEK			SEK 844
Foreign exchange contracts | NOK | Buy
Derivatives
Number of contracts	1	1	1	1	1	1
Aggregate notional amount | NOK	NOK 8
Foreign exchange contracts | NOK | Sell
Derivatives
Number of contracts	1	1	1	1	1	1
Aggregate notional amount | NOK	NOK 878
Foreign exchange contracts | DKK | Buy
Derivatives
Number of contracts	1	1	1	1	1	1
Aggregate notional amount | DKK				DKK 69
Foreign exchange contracts | DKK | Sell
Derivatives
Number of contracts	1	1	1	1	1	1
Aggregate notional amount			SEK 7,032	DKK 6,251
Interest rate swaps | Paying fixed rates
Derivatives
Number of contracts	37	37	37	37	37	37
Aggregate notional amount | $						$ 281,472
Interest rate swaps | Receiving fixed rates
Derivatives
Number of contracts	1	1	1	1	1	1
Aggregate notional amount | $						$ 8,000
Interest rate swaps | Derivatives designated as hedging instruments
Derivatives
Number of contracts | instrument	6	6	6	6	6	6
Aggregate notional amount | $						$ 69,500
Fixed monthly coupons at fixed rate, low end of range (as a percent)	0.60%	0.60%	0.60%	0.60%	0.60%	0.60%
Fixed monthly coupons at fixed rate, high end of range (as a percent)	1.52%	1.52%	1.52%	1.52%	1.52%	1.52%
Amount expected to be reclassified from other comprehensive income to interest expense over the next twelve months | $						$ 200
Hedging period for covering exposure to the variability in future cash flows	62 months
Interest rate caps | EUR
Derivatives
Number of contracts	2	2	2	2	2	2
Aggregate notional amount | €					€ 294,000
Interest rate caps | USD
Derivatives
Number of contracts	4	4	4	4	4	4
Aggregate notional amount | $						$ 34,543
Credit index instruments
Derivatives
Number of contracts	9	9	9	9	9	9
Aggregate notional amount | $						$ 36,000