Equity Change in OCI Recognized in Statement of Operations, Line Item (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of investments, net									$ (613)	$ 376	$ 521
Interest expense deposits									39,846	20,884	16,571
Income tax expense/(benefit)	$ 8,651	$ 5,461	$ 17,399	$ 6,026	$ 21,391	$ 8,289	$ 9,963	$ 6,553	37,537	46,196	30,963
Net income attributable to the Company	$ 33,302	$ 17,962	$ 6,434	$ 22,686	$ (18,280)	$ 19,803	$ 23,406	$ 15,662	80,384	40,591	71,628
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax									646	(688)	(979)
Unrealized gain/ (loss) on securities available-for-sale
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax									(426)	222	331
Unrealized gain/ (loss) on securities available-for-sale | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of investments, net									(596)	376	521
Income tax expense/(benefit)									(170)	154	190
Net income attributable to the Company									(426)	222	331
Unrealized gain/ (loss) on cash flow hedges, before 2017-12 adoption
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax										(688)	(979)
Unrealized gain/ (loss) on cash flow hedges, before 2017-12 adoption | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense deposits										1,179	1,666
Income tax expense/(benefit)										491	687
Net income attributable to the Company										$ (688)	$ (979)
Unrealized gain/ (loss) on cash flow hedges, after 2017-12 adoption
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax									646
Unrealized gain/ (loss) on cash flow hedges, after 2017-12 adoption | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense deposits									(907)
Income tax expense/(benefit)									(261)
Net income attributable to the Company									$ 646