Allowance for Doubtful Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in allowance for doubtful accounts
Balance at beginning of year	$ 1,228	$ 1,048	$ 1,051
Provision charged to expense	1,145	1,710	938
Accounts written off, net of recoveries	1,186	1,530	941
Balance at end of year	1,187	1,228	1,048
Components of allowance for doubtful accounts
Allowance for doubtful accounts related to accounts receivable-customer	755	797	715
Allowance for doubtful accounts related to receivable from U.S. government	0	8	0
Allowance for doubtful accounts related to other accounts receivable	432	423	333
Total allowance for doubtful accounts	1,187	1,228	1,048
GSWC
Changes in allowance for doubtful accounts
Balance at beginning of year	1,177	1,005	1,005
Provision charged to expense	1,056	1,668	859
Accounts written off, net of recoveries	1,119	1,496	859
Balance at end of year	1,114	1,177	1,005
Components of allowance for doubtful accounts
Allowance for doubtful accounts related to accounts receivable-customer	755	797	715
Allowance for doubtful accounts related to other accounts receivable	359	380	290
Total allowance for doubtful accounts	$ 1,114	$ 1,177	$ 1,005