Consolidated Statements of Changes in Shareholders' Equity (unaudited) - USD ($) $ in Thousands	Total	Anchor BanCorp Wisconsin Inc. [Member]	Common Stock [Member]	Common Stock [Member] Anchor BanCorp Wisconsin Inc. [Member]	Capital Surplus [Member]	Capital Surplus [Member] Anchor BanCorp Wisconsin Inc. [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2015	$ 1,491,170		$ 114,297		$ 1,087,911		$ 323,759	$ (34,797)
Net income	66,099						66,099
Other comprehensive income	11,180							11,180
Acquisition		$ 273,565		$ 20,415		$ 253,150
Dividends-common stock	(32,391)						(32,391)
Common stock issued	202		17		185
Common stock repurchased	(1,546)		(120)		(1,426)
Stock-based compensation expense	3,391				3,391
Stock activity under incentive compensation plans	(553)		396		(818)		(131)
Ending Balance at Jun. 30, 2016	1,811,117		135,005		1,342,393		357,336	(23,617)
Beginning Balance at Mar. 31, 2016								(29,585)
Net income	39,122
Other comprehensive income	5,968
Ending Balance at Jun. 30, 2016	1,811,117		135,005		1,342,393		357,336	(23,617)
Beginning Balance at Dec. 31, 2016	1,814,417		135,159		1,348,338		390,292	(59,372)
Net income	74,846						74,846
Other comprehensive income	28,252							28,252
Dividends-common stock	(35,219)						(35,219)
Common stock issued	188		11		177
Common stock repurchased	(1,852)		(104)		(1,748)
Stock-based compensation expense	3,184				3,184
Stock activity under incentive compensation plans	2,778		450		2,460		(132)
Ending Balance at Jun. 30, 2017	1,886,594		135,516		1,352,411		429,787	(31,120)
Beginning Balance at Mar. 31, 2017								(48,565)
Net income	38,854
Other comprehensive income	17,445
Ending Balance at Jun. 30, 2017	$ 1,886,594		$ 135,516		$ 1,352,411		$ 429,787	$ (31,120)