Condensed Consolidating Financial Statements (Details 4) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Operating activities:    
Net income (loss) $ 1,575 $ (5,476)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:    
Depreciation and amortization 15,736 16,564
Change in value of life insurance contracts (161) (158)
Other changes in noncurrent assets and liabilities 6,535 (9,034)
Changes in operating assets and liabilities:    
Other changes, net   8,577
Changes in operating assets and liabilities: 3,204  
Net cash provided by operating activities 26,889 10,473
Investing activities:    
Utility plant expenditures (35,047) (24,620)
Purchase of life insurance   (1,674)
Changes in restricted cash and other changes, net (26) 418
Net cash (used in) investing activities (35,073) (25,876)
Financing Activities:    
Short-term borrowings 30,000 22,200
Repayment of short-term borrowings   (5,000)
Proceeds from long-term debt 50  
Repayment of long-term debt (338) (460)
Advances and contributions in aid of construction 1,777 2,194
Refunds of advances for construction (1,574) (1,535)
Dividends paid to non-affiliates (8,007) (7,758)
Net cash provided by financing activities 21,908 9,641
Change in cash and cash equivalents 13,724 (5,762)
Cash and cash equivalents at beginning of period 19,587 27,506
Cash and cash equivalents at end of period 33,311 21,744
Consolidating Adjustments    
Operating activities:    
Net income (loss) (1,390) 5,697
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:    
Equity earnings of subsidiaries 1,405 (5,681)
Dividends received from affiliates (8,007) (7,758)
Depreciation and amortization (25) (27)
Other changes in noncurrent assets and liabilities 94 11
Changes in operating assets and liabilities:    
Changes in operating assets and liabilities: (84)  
Net cash provided by operating activities (8,007) (7,758)
Investing activities:    
Investment in affiliates 1,000  
Changes in affiliate advances 667 1,660
Proceeds from affiliates long-term debt (243) (230)
Net cash (used in) investing activities 1,424 1,430
Financing Activities:    
Investment from affiliates (1,000)  
Changes in affiliate advances (667) (1,660)
Repayment of affiliates long-term borrowings 243 230
Dividends paid to affiliates 8,007 7,758
Net cash provided by financing activities 6,583 6,328
Parent Company    
Operating activities:    
Net income (loss) 1,575 (5,476)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:    
Equity earnings of subsidiaries (1,405) 5,681
Dividends received from affiliates 8,007 7,758
Depreciation and amortization 57 43
Other changes in noncurrent assets and liabilities 1,109 772
Changes in operating assets and liabilities:    
Other changes, net   (229)
Changes in operating assets and liabilities: (1,151)  
Net cash provided by operating activities 8,192 8,549
Investing activities:    
Investment in affiliates (1,000)  
Changes in affiliate advances (3,220) (2,989)
Proceeds from affiliates long-term debt 243 230
Net cash (used in) investing activities (3,977) (2,759)
Financing Activities:    
Short-term borrowings   2,200
Repayment of short-term borrowings   (5,000)
Dividends paid to non-affiliates (8,007) (7,758)
Net cash provided by financing activities (8,007) (10,558)
Change in cash and cash equivalents (3,792) (4,768)
Cash and cash equivalents at beginning of period 4,108 5,280
Cash and cash equivalents at end of period 316 512
Cal Water    
Operating activities:    
Net income (loss) 2,030 (4,520)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:    
Depreciation and amortization 14,575 15,424
Change in value of life insurance contracts (161) (158)
Other changes in noncurrent assets and liabilities 10,717 (9,176)
Changes in operating assets and liabilities:    
Other changes, net   7,582
Changes in operating assets and liabilities: (2,185)  
Net cash provided by operating activities 24,976 9,152
Investing activities:    
Utility plant expenditures (33,793) (22,896)
Changes in affiliate advances 2,725 1,510
Purchase of life insurance   (1,674)
Changes in restricted cash and other changes, net (26) 418
Net cash (used in) investing activities (31,094) (22,642)
Financing Activities:    
Short-term borrowings 30,000 20,000
Changes in affiliate advances 1,309 356
Repayment of long-term debt (197) (304)
Advances and contributions in aid of construction 1,759 1,735
Refunds of advances for construction (1,573) (1,521)
Dividends paid to affiliates (7,909) (7,469)
Net cash provided by financing activities 23,389 12,797
Change in cash and cash equivalents 17,271 (693)
Cash and cash equivalents at beginning of period 13,929 20,790
Cash and cash equivalents at end of period 31,200 20,097
All Other Subsidiaries    
Operating activities:    
Net income (loss) (640) (1,177)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:    
Depreciation and amortization 1,129 1,124
Other changes in noncurrent assets and liabilities (5,385) (641)
Changes in operating assets and liabilities:    
Other changes, net   1,224
Changes in operating assets and liabilities: 6,624  
Net cash provided by operating activities 1,728 530
Investing activities:    
Utility plant expenditures (1,254) (1,724)
Changes in affiliate advances (172) (181)
Net cash (used in) investing activities (1,426) (1,905)
Financing Activities:    
Investment from affiliates 1,000  
Changes in affiliate advances (642) 1,304
Repayment of affiliates long-term borrowings (243) (230)
Proceeds from long-term debt 50  
Repayment of long-term debt (141) (156)
Advances and contributions in aid of construction 18 459
Refunds of advances for construction (1) (14)
Dividends paid to affiliates (98) (289)
Net cash provided by financing activities (57) 1,074
Change in cash and cash equivalents 245 (301)
Cash and cash equivalents at beginning of period 1,550 1,436
Cash and cash equivalents at end of period $ 1,795 $ 1,135