PARENT COMPANY STATEMENTS, Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues [Abstract]
Other income	$ 123,299	$ 119,020	$ 102,180
Expenses [Abstract]
Interest on borrowings	2,537	2,477	2,520
Other expenses	13,521	17,310	14,971
Income before tax benefit and equity in undistributed net income of subsidiaries	132,217	129,690	111,027
Income tax (expense)/benefit	(40,987)	(38,337)	(32,198)
Net income	91,230	91,353	78,829
Comprehensive income/(loss)	79,745	148,619	(2,051)
Parent Company [Member]
Revenues [Abstract]
Dividends from subsidiaries	76,000	61,100	66,000
Interest and dividends on investments	94	88	91
Other income	0	0	9
Total revenues	76,094	61,188	66,100
Expenses [Abstract]
Interest on borrowings	2,537	2,477	2,520
Other expenses	19	37	61
Total expenses	2,556	2,514	2,581
Income before tax benefit and equity in undistributed net income of subsidiaries	73,538	58,674	63,519
Income tax (expense)/benefit	(572)	581	862
Income before equity in undistributed net income of subsidiaries	72,966	59,255	64,381
Equity in undistributed net income of subsidiaries	18,264	32,098	14,448
Net income	91,230	91,353	78,829
Comprehensive income/(loss)	$ 79,745	$ 148,619	$ (2,051)