Derivatives and Hedging Activity - Designated and Non-Designated Hedges (Details) - 6 months ended Jun. 30, 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	258	258	258	258	258	258
Foreign exchange contracts | GBP | Sell
Derivatives
Number of contracts	81	81	81	81	81	81
Aggregate notional amount | £		£ 150,831
Foreign exchange contracts | EUR | Buy
Derivatives
Number of contracts	2	2	2	2	2	2
Aggregate notional amount | €					€ 94
Foreign exchange contracts | EUR | Sell
Derivatives
Number of contracts	93	93	93	93	93	93
Aggregate notional amount | €					€ 364,047
Foreign exchange contracts | EUR | Sell | Ireland Portfolio
Derivatives
Number of contracts	49	49	49	49	49	49
Aggregate notional amount | €					€ 246,900
Foreign exchange contracts | SEK | Buy
Derivatives
Number of contracts	2	2	2	2	2	2
Aggregate notional amount | SEK			SEK 1,321
Foreign exchange contracts | NOK | Buy
Derivatives
Number of contracts	2	2	2	2	2	2
Aggregate notional amount | NOK	NOK 15
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	2	2	2	2	2	2
Aggregate notional amount | DKK				DKK 137
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	56	56	56	56	56	56
Aggregate notional amount | $						$ 370,206
Interest rate swaps | Receiving fixed rates
Derivatives
Number of contracts	2	2	2	2	2	2
Aggregate notional amount | $						$ 9,800
Interest rate swaps | Derivatives designated as hedging instruments
Derivatives
Number of contracts | instrument	6	6	6	6	6	6
Aggregate notional amount | $						$ 66,400
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 | $						$ 300
Hedging period for covering exposure to the variability in future cash flows	59 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 | $						$ 34,474
Credit index instruments
Derivatives
Number of contracts	9	9	9	9	9	9
Aggregate notional amount | $						$ 36,000